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COPYRIGHT DEPOSIT. 



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This volume, which is No. 21 in the Series, was 
edited by J. Carleton Bell 



DEFICIENCY AND DELINQUENCY 

An Interpretation of Mental Testing 



Deficiency and Delinquency 

An Interpretation of Mental Testing 



BY 
JAMES BURT MINER, LL.B., PH.D. 

Associate Professor of Applied Psychology, Carnegie Institute of 

Technology, Pittsburgh ; sometime lecturer at the school for 

teachers of special classes, Minnesota State School 

for the Feeble-Minded 



BALTIMORE 

WARWICK & YORK, Inc. 

1918 






Copyright, 191 8 
Warwick & York, Inc. 



JAN 18 1919 
©CLA530574 



ded 



DEFICIENCY AND DELINQUENCY 



h 



TABLE OF CONTENTS 

Chapter I. INTRODUCTION.' '.'/.'.'.'.'/.'.'.'.'.'.'.'/.'.[ 3 

PART I. PRACTICAL CONSIDERATIONS 

Chapter II. THE FUNCTIONS OF A SCALE IN 
DIAGNOSIS 10 

A. The Meaning of Intellectual Defici- 

ency 10 

B. Forms of Mental Deficiency Not Yet 

Discoverable by Tests 14 

C. Doubtful Intellects Accompanied by 

Delinquency Presumed Deficient. . . 18 
Chapter III. THE PERCENTAGE DEFINITION 
OF INTELLECTUAL DEFICIENCY 20 

A. The Definition 20 

B. The Assumptions of a Quantitative De- 

finition ; 21 

(a) Deficiency is a Difference in Degree 

not in Kind 21 

(b) As to the Variation in the Frequency 

of Deficiency at Different Ages . . 23 

(c) As to the Number of Deficients not 

Detected by Tests 34 

(d) Allowance May be Made for Vari- 

ability 40 

Chapter IV. WHAT PERCENTAGE IS FEEBLE- 
MINDED 47 

A. Kinds of Social Care Contemplated ... 47 

B. Estimates of the School Population 

Versus the General Population 48 

C. Desirable Versus Immediately Advis- 

able Social Care 51 

D. Percentages Suggested to Harmonize 

the Estimates 52 

E. Comparison With Important Estimates 56 

F. The Ability of the Mentally Retarded 

Especially Those Receiving Special 
Training 74 

(ix) 



X TABLE OF CONTEXTS 

Chapter V. ADAPTING THE PERCENTAGE DE- 
FINITION TO THE BINET SCALE 82 

A. The Border Region for the Mature ... 82 

a Indication from a Random Group.. 82 

(b) The Present Tendency Among Ex- 

aminers 95 

B. The Border Region for the Immature 104 

(a) For the Binet 1908 Scale 104 

b Data for Other Developmental 

Scales 110 

(c) The Change in Interpreting the 

Borderline for the Immature 116 

Chapter VI. DELINQUENTS TESTING DEFICI- 
ENT 122 

A. At the Glen Farm School for Boys. 

Hennepin County, Minnesota 122 

B. Comparison of Tested Deficiency 

Among Typical Groups of Delin- 
quents 12, 

a Women and Girl Delinquents in 

State Institutions 128 

b. Women and Girl Delinquents in 

Country and City Institutions . . . 134 
c Men and Boy Delinquents in State 

Institutions 141 

d Men and Boy Delinquents in County 

and City Institutions 148 

C. Summary of Tested Deficiency Among 

Delinquents 158 

Chapter VII. CHECKING THE BINET DIAG- 
NOSIS BY OTHER METHODS 17C 

Chapter VIII. SCHOOL RETARDATION AMONG 
DELINQUENTS 177 

A. In Minneapolis 177 

B. School Retardation Among Other 

Groups of Delinquents 185 

Chapter IX. COMPARISON OF THE SCHOOL 

TEST AND THE BINET TEST 189 

A. Practical Uses of the School Test .... 190 



TABLE OF CONTENTS XI 

(a) Estimating the Frequency of Defi 

ciency by School Retardation .... 190 

(b) School Retardation as a Warning of 

the Need for Examination 194 

(c) School Success as a Check on the 

Binet Diagnosis 197 

B. Checking Deficiency Among Delin- 
quents by the School Test 199 

Chapter X. BAD SCHOOL ADJUSTMENT AS A 
CAUSE OF DELINQUENCY 203 

Chapter XL DEFICIENCY AS A CAUSE OF DE- 
LINQUENCY. . 210 

A. The Chances of the Mentally Defi- 

cient Becoming Delinquent 211 

B. The Correlation of Deficiency and De- 

linquency 218 

C. The Causes of Delinquency 224 

(a) Constitutional Factors 224 

(b) External Factors 225 

(c) Weighing Heredity Against Environ- 

ment 229 

(d) The Criminal Diathesis 234 

Chapter XII. SUMMARY AND SUGGESTIONS. 239 

PART II. THEORETICAL CONSIDER- 
ATIONS 

Chapter XIII. THE THEORY OF THE MEAS- 
UREMENT OF MENTAL DEVELOPMENT. . 252 

A. Comparison of Units and Scales for 

Measuring Individual Differences . . 254 

(a) Equivalent Units of Ability When 

the Distributions are Normal .... 254 

(b) The Year Unit of the Binet Scale. . 260 

(c) Is Tested Capacity Distributed Nor- 

mally? 267 

(d) Equivalent Units of Development 

When the Form of Distribution is 
Uncertain 275 

B. The Curves of Mental Development . . 279 



Xll TABLE OF CONTENTS 

(a) The Significance of Average Curves 

of Development 280 

(b) Changes in the Rate of Development 290 

(c) The Question of Earlier Arrest of De- 

ficient Children 294 

Chapter XIV. QUANTITATIVE DEFINITIONS 
OF THE BORDERLINE 304 

A. Different Forms of Quantitative De- 

finitions 304 

B. Common Characteristics of Quantita- 

tive Definitions 308 

C. Practical Advantages of the Percent- 

age Method 311 

D. Theoretical Advantage of the Percent- 

age Method with Changes in the 
Form of the Distributions 317 

BIBLIOGRAPHY ON TESTED DELINQUENTS 324 

Other References Cited 329 

APPENDICES 344 

INDEX 353 



LIST OF TABLES AND FIGURES 

Tables 

I. Age distribution of deaths in the general 
population and of feeble-minded in institu- 
tions 30 

II. Mortality of institutional deficients in the 
United States compared with the general 
population 31 

III. Test borderlines with randomly selected 

Minneapolis 15-year-olds 89 

IV. Results with the Binet tests for mental ages 

XI and XII (1908 series) 98 

V. Percentages of mentally retarded children as 

tested with the Binet 1908 Scale 106 

VI. Mental retardation of children as tested with 

the Binet 1911 Scale Ill 

VII. Borderlines with the Point Scale 115 

VIII. Test ages of the Glen Lake group of delin- 
quent boys 124 

IX. Intellectual development relative to life-ages 
and school positions among the delinquent 

boys of Glen Lake 125 

X. Binet 1911 tests of boys consecutively ad- 
mitted to the Detention Home at Thorn 

Hill, Allegheny County 151 

XL Frequency of tested deficiency among over 

9000 delinquents 159 

XII. Age and grade distribution of elementary 

school pupils in Minneapolis 178 

XIII. School retardation of Minneapolis delin- 

quents and elementary school pupils 179 

XIV. Indices of frequency and amount of school 

retardation for Minneapolis delinquents 

and elementary school pupils 183 

XV. Percentage of pupils 12 and 13 years of age 

most seriously retarded in school 193 

XVI. School position of delinquents at Glen Lake 

relative to their intellectual development . 204 

(xiii) 



XIV TABLES AND FIGURES 

XVII. Goring's data as to the percentage of mental 
defectives among men convicted of various 

offenses 213 

XVIII. Goring's data as to groups of crimes commit- 
ted most frequently bv those mentally de- 
ficient 214 

XIX. Four-fold correlation table for juvenile delin- 
quency and deficiency in Minneapolis .... 222 
XX. Average Intelligence Quotients of children of 

different ability 296 

XXI. Test records with random 15-year-olds 344 

XXII. Test records with delinquents at the Glen 

Lake Farm School 349 

Figures 

1. Mortality among feeble-minded in institutions 

compared with the general population 32 

2. School retardation of Minneapolis delinquents 

compared with elementary school boys 180 

3. Hypothetical development curves (normal distri- 

butions) 253 

4. The question of equivalence of year units 265 

5. Hypothetical development curves (changing form 

of distribution.) 277 

6. Tests of the development of memory processes. 

Medians at each age for the central tendencies of 
the tests 285 

7. Different types of development. Medians at each 

age for the central tendencies of the tests 286 

8. Forty tests of development. Distribution at each 

age for the central tendencies of the tests 287 

9. Relative positions at each age of the median and 

of corresponding bright and retarded children 
with the Form Board Test 299 



DEFICIENCY AND DELIQUENCY 



PREFACE 

In undertaking in 1912 to examine the mental develop- 
ment of delinquents for the clinic started and supported 
by the Juvenile Protective League of Minneapolis, in con- 
nection with the Juvenile Court, I soon became convinced 
that a safer method for evaluating the limit of feeble- 
mindedness with tests was more needed than masses of 
new data. The researches that have been published in 
the past three years do not seem to have changed this sit- 
uation. Numerous studies with psychological tests are 
already available, but they generally treat of average 
rather than borderline conditions. In the field of delin- 
quency the work of testing has been carried on with espe- 
cial activity. Here, as well as elsewhere, the conclusions 
seem likely to be misleading unless social workers better 
appreciate the real place of mental tests, their value and 
their limitations. 

The tables of a few hundred juvenile delinquents and 
school children examined in Minneapolis, which are 
presented in this book, indicate the occasion rather than 
the aim of the present study. The purpose is mainly to 
help clear the ground for other work with mental tests, 
and especially to put the determination of feeble-minded- 
ness by objective examination with the Binet or other 
scales on what seems to me a sounder basis. Further- 
more, the results of objective testing which have been so 
rapidly accumulating in the field of delinquency need to 
be assembled and reorganized in order to avoid confusion. 
It is especially desirable to discover a conservative basis 
for objective diagnosis of deficient intellectual capacity 
in order to prevent very useful testing systems from be- 
coming unjustly discredited and to preserve the advance 
that has been made. 

(l) 



2 PREFACE 

The work out of which this monograph grew was begun 
through the encouragement of Judge Edward F. Waite of 
the Hennepin County Juvenile Court. His earnest co- 
operation and my interest in the field of mental testing 
has led me to continue the study. Judge Waite's in- 
sight into his court problems resulted in the early organiza- 
tion of a Juvenile Court clinic {153 > 170) in Minneapolis. 
The clinic is in charge of Dr. Harris Dana Newkirk, who 
has contributed materially to this study by his thorough 
medical examination of each of the cases brought to him. 
To the staff at the probation office I am also much in- 
debted. 

The earnest help of Superintendent D. C. MacKenzie, 
of the Glen Lake Farm School for the juvenile delinquents 
of Hennepin County, made a close study of our most in- 
teresting group of boys much more profitable personally 
than I have shown here. For detailed expert work in tab- 
ulation and in examinations I wish to express my thanks 
to my advanced students, a half dozen of whom have 
contributed materially to the data of this book. 

James Burt Miner. 

Carnegie Institute of Technology 
Pittsburgh, Pa. 



CHAPTER I. INTRODUCTION 

As an interpretation of the results which have been ob- 
tained with mental tests, this book lies between the topics 
of deficiency and delinquency. It is an attempt to dis- 
cover the significance of objective measurements of abil- 
ity in connection with both of these fields. The pressing 
practical problem was to find out what positions on a 
scale for testing mental development were symptomatic 
of social deficiency. After working out a percentage 
method for conservatively indicating these borderlines for 
tested deficiency, it was then possible to reinterpret the 
test records of over 9000 delinquents who have been ex- 
amined with some form of the well-known Binet Scale. 
The size of the problem of the deficient delinquent has 
thus been determined on a significant scientific plan. 
The outcome is a new basis for judging the current state- 
ments about this problem by those who have used the 
Binet scale. Scores of investigators by their tireless 
energy have provided data which may now be compared 
for many types of delinquents and in many parts of the 
country. Some sixty studies of deficient delinquents have 
been thus summarized from the point of view of psycholog- 
ical tests. 

Closely related to the problem of the frequency of feeble- 
mindedness among delinquents is the question of the cause 
of delinquency. This has further been considered in the 
light of the most important scientific studies, especially 
those using the method of correlation. Among these re- 
searches stands out the fundamental investigation of the 
causes of criminality by Goring, a work which has received 
very inadequate attention in this country, although it in- 
volved ten years study of a group of 3000 convicts by the 

3 



4 DEFICIENCY AND DELINQUENCY 

best quantitative methods. The careful study of these 
objective investigations should take the question of the 
relation of deficiency and delinquency out of the realm of 
opinion and theory. It may be expected to have an im- 
portant influence upon the social handling of these prob- 
lems. In this connection I have added a chapter of sug- 
gestions which have grown out of my year's study of the 
education of deficients and delinquents in European schools 
and institutions. 

To determine the size of the problem of dealing with 
deficients, especially deficient delinquents, is a task of 
first importance. In spite of our more conservative basis 
for judging the results with tests, the necessity of caring 
for the feeble-minded remains the most vital problem 
connected with social welfare. The movement for more 
individual training in our schools, which has been gaining 
such headway, may also be encouraged by the evidence 
that mal-adjustment to school work is also definitely re- 
lated to delinquency. 

It is essential that we should have objective data for 
determining the borderline of tested deficiency among 
adults. To meet the present serious lack of knowledge 
on this point, new data were collected which for the first 
time afford the means of determining, by the use of a 
randomly selected group what is a conservative borderline 
of tested deficiency for those intellectually mature. These 
data include the Binet test records for all the 15-year-old 
children who resided in seven school districts in Minne- 
apolis and who had not graduated from the eighth grade. 

The urgency of plans for indefinitely segregating certain 
types of the feeble-minded, especially deficient delinquents, 
has placed a new emphasis on those quantitative aids to 
diagnosis. The difficulty of establishing feeble-minded- 
ness before a court has been called to attention by both 



INTRODUCTION 5 

Supt. C. A. Rogers (173)* of the Minnesota School for 
Feeble-Minded, and Supt. Walter E. Fernald (104) of the 
Massachusetts School. Both of these men recognize that 
psychological tests are the most hopeful way of improving 
this situation. 

A fundamental feature of the diagnosis of deficiency is 
the plan here advocated for designating the borderlines 
on a scale on the basis of a percentage definition of tested 
deficiency. This involves the distinction of intellectual 
deficiency from certain rare volitional forms of feeble- 
mindedness, which the tests do not at present detect. 
This percentage definition seems to afford the best ap- 
proach to a test diagnosis. It is apparent that the data 
are insufficient for finally establishing such a quantitative 
description of the lower limit for passable intellects on a 
mental scale. The plan, however, may be easily adjusted 
to new data, and meanwhile avoids some of the serious 
current misinterpretations of test results. 

While the idea of a quantitative definition of the border- 
line of deficiency is not new, the percentage method seems 
to have certain fundamental advantages over either the 
"intelligence quotient' ' of Stern (188) , the "intelligence 
coefficient" of Yerkes (226), or the description in terms of 
deviation, mentioned by Norsworthy (159) and Pearson 
(164, 166, 167). Several investigators, including Terman 
(57) and Yerkes (226), are utilizing the percentage method 
indirectly for describing the borderline of feeble-minded- 
ness, but have inadequately distinguished it from the 
ratios. While ratio and deviation methods are possibly 
more serviceable for certain purposes, they are especially 
faulty near the borderline of deficiency, since they are 
affected by variations in the units of measurement and in 

*Numbers in parenthesis indicate the references in the bibliography 
at the close of the book. 



6 DEFICIENCY AND DELINQUENCY 

the form of distribution from age to age. My paper on 
a percentage definition and the detailed plan for deter- 
mining the borderline in the Binet scale, which was read 
at the meeting of the American Psychological Association 

in 1915, seems to have been contemporaneous with a sim- 
ilar suggestion by Pintner and Paterson (44). They, 
however, would restrict the term "feeble-mindedness" to 
tested deficiency, while I advocate the use of percentage 
borderlines on a test scale as symptomatic of one form 
of feeble-mindedness, much as excess of normal temper- 
ature on a clinical thermometer is symptomatic of disease. 
Although no system of objective tests will ever dispense 
with the need for expert interpretation in diagnosing in- 
dividual cases, still there are few who would doubt that 
it is desirable to reduce the option of expert judgment as 
much as we reasonably can. This is the scientific method 
of procedure. The borderline cases, however, w r hich are 
often most troublesome in their delinquencies, are just 
those which will longest defy rigid rules, The diagnos- 
tician who wants to be as free as possible from external 
restraint will find in this border field of mental capacity 
a happy hunting ground. His scientific instincts should 
make him eager to discover when he leaves the mundane 
sphere and sallies forth into uncharted realms where he 
bears the full responsibility of his own opinion. Let me 
hasten to add that reasoning from objective data in the 
mass to the diagnosis of an individual case may lead to 
serious mistakes, unless one keeps alert to detect the ex- 
ception from the general rule, and unless one understands 
the numerous sources of error entering into an examina- 
tion. On the other hand the test results when properly 
interpreted afford the most important criteria on which 
to base a prognosis if they are considered in relation to the 
history of the case and the medical examination. 



INTRODUCTION 7 

By the use of more conservative borderlines for raising 
the presumption of deficiency and also by designating a 
doubtful position on the scale, on the plan advocated 
herein, it is possible to make scales for testing mental 
capacity more serviceable both to the clinician and to the 
amateur tester. The latter may use the scales for his 
own information or may wish to discover whether an ex- 
amination by an expert in mental development is desirable, 
without attempting to make a diagnosis himself. The 
scale may thus take a place in the study of child mentality 
analogous to the familiar Snellen chart in the testing of 
vision. For every teacher familiarity with a develop- 
ment scale may thus become as essential and desirable as 
the knowledge of the chart for eye testing. It should 
find a place in all progressive schools which do not have 
the services of a clinician. 

The Binet system of tests was used for obtaining new 
data on groups of juvenile delinquents in Minneapolis 
and Pittsburgh. The use of this scale, around which the 
discussion centers, grew out of the necessity for immediate 
practical results for the clinic at the Minneapolis Juvenile 
Court which I was called upon to Serve. In 1912, when 
that work began, there was practically nothing approach- 
ing norms with children for any other scale of tests. Even 
today it is plain that there is more data available for in- 
terpreting results with the Binet scale than with any other 
system of tests. While my experience would make me 
unwilling to advocate the Binet tests as an ideal method 
for building up a measuring scale, I still feel that it remains 
the most useful method at present for discovering the fund- 
amental symptoms of intellectual deficiency. The per- 
centage method, here advocated, as the best way available 
for determining the borderlines with a scale, would be 
quite as serviceable, however, with any other testing sys- 



8 DEFICIENCY AND DELINQUENCY 

tern. It has been my aim to contribute to the interpreta- 
tion of the results of the tests as they are, not to perfecting 
the arrangement or details of the separate tests.* It 
happens that one of the main objections which has been 
raised to the Binet scale, the inadequacy of its tests for 
the older ages, loses its force so far as the diagnosis oj 
feeble-mindedness is concerned for those who accept the 
borderlines described in this paper. 

Some diagnosticians may hesitate to use the Binet scale 
because of the criticisms it has received. Yerkes and 
Bridges state: "Indeed, we feel bound to say that the 
Binet scale has proved worse than useless in a very large 
number of cases" {226, p. 94). So far as this objection 
arises from the attempt to use the descriptions of the bor- 
derline of feeble-mindedness published with Binet scales, 
it will meet with a wide response. The difficulty is hardly 
less, as I shall show, with other scales. The definition of 
the borderline is certainly the vital point with any objec- 
tive method for aiding diagnosis. Only by improving 
methods for determining the borderline can this weakness 
be attacked. The central contribution of this paper is 
directed, therefore, to this problem of the interpretation 
of the borderline, so that objective scales may be made 
more reliable for purposes of diagnosis. 

In Part Two I have added an intensive discussion of 
the measurement of development and a comparison of the 
different objective methods for describing the border- 
line. This may well be omitted by those who are not in- 
terested in the technical aspects of these questions. To 
those who care only for accounts of individual lives, let 



"Those concerned with other features of the Binet scale will find an 
admirable bibliography by Samuel C. Kohs, Journal of Educational 
Psychology, April, May and June, 1914, and September, October, Nov- 
ember, and December, 1917. Other references are contained in the 
Bibliography by L. W. Crafts (9). 



INTRODUCTION 9 

me say that I am contributing nothing herein to that im- 
portant field which has been covered in authoritative form 
by Dr. Healy (27) and by Dr. Goddard (112). They will 
find instead, I hope, the fascination of figures, a picture 
book in which probability curves take the place of photo- 
graphs and biographies, in which general tendencies are 
evaluated and attention is focussed upon the problem of 
properly diagnosing deficiency and upon plans for the 
care of the feeble-minded, whether they be potential or 
actual delinquents. 



PART ONE 
PRACTICAL CONSIDERATIONS 

CHAPTER II. THE FUNCTIONS OF A SCALE 
IN DIAGNOSIS 

A. The Meaning of Intellectual Deficiency. 

_ Whatever form the definition of feeble-mindedness may 
take, in this country at least* the concept has become 
quite firmly established as describing the condition of 
those who require social guardianship, because, with 
training, they do not develop enough mentally to live an 
independent life in society. The feeble-minded are social- 
ly deficient because of a failure to develop mentally. They 
are proper wards of the state because of this mental de- 
ficiency. Goddard says, they are "incapable of function- 
ing properly in our highly organized society" (112 > p. 6). 
The most generally quoted verbal description of the upper 
line of social unfitness is that of the British Royal Com- 
mission on Feeble-Mindedness: ' 'Persons who may be 
capable of earning a living under favorable circumstances, 
but are incapable from mental defect existing from birth 
or from an early age (a) of competing on equal terms with 
their normal fellows; or (b) of managing themselves and 
their affairs with ordinary prudence/ ' It is clear that 
the intention is to distinguish mental deficiency from senile 
dementia, from hysteria and from insanity, in which there 
is a temporary or permanent loss of mental ability rather 
than a failure to develop. Feeble-mindedness may, how- 
ever, arise from epilepsy or from other diseases or accidents 
in early life as well as from an inherent incapacity for de- 



*In Great Britain the term is restricted to those above the imbecile 
group. 

(10) 



FUNCTIONS OF A SCALE 11 

velopment. Moreover, mental deficiency, or feeble-mind- 
edness, (I use the terms interchangeably) does not imply 
that the social unfitness is always caused by intellectual 
deficiency. Mind is a broader term than intellect, as we 
shall note in the next section. 

This definition of the feeble-minded is the main idea 
expressed by Witmer (221), Tredgold (204), Pearson (164), 
and Murdock (164). The historical development of the 
concept is traced by Rogers (172) and Norsworthy (159). 
It is criticized by Kuhlmann (140) as impractical and in- 
definite. The indefiniteness is indicated by such terms 
as ' 'under favorable circumstances/ ' "on equal terms," 
and "with ordinary prudence." This objectionable un- 
certainty as to social fitness can be considerably relieved 
for those types of feeble-mindedness which involve the 
inability to pass mental tests, since this result can later 
be correlated with subsequent social failure and predic- 
tions made during childhood on the basis of the tests. 
Attempts to make the concept of feeble-mindedness more 
definite have, therefore, naturally taken some quantitative 
form in relation to objective tests. Binet and the French 
commission in 1907 (77) called attention to the method 
in use in Belgium for predicting unfitness objectively on 
the basis of the amount of retardation in school at differ- 
ent ages. With the appearance in 1908 of the Binet- 
Simon revised scale for measuring mental development, 
quantitative descriptions began to be concerned with the 
borderlines of mental deficiency on scales of tests. 

While the quantitative descriptions of tested deficiency 
do not include all forms of feeble-mindedness, as I shall 
show in the next section, they have made the diagnosis of 
the majority of cases much more definite. Nobody would 
think of returning to the days when the principal objective 
criteria were signs of Cretinism, Mongolianism, hydro- 



12 DEFICIENCY AND DELINQUENCY 

cephalus, microcephalus, epilepsy, meningitis, etc-, which 
Lapage (141) has shown are not found among more than 
9 : " of 784 children in the Manchester special schools. 
The impossibility of agreeing upon subjective estimates of 
mental capacity without the use of objective criteria is 
well shown by Binet's methodical comparison of the ad- 
mission certificates filled out within a few days erf each 
other by the alienists for the institutions erf Sainte-Aime, 
Bicetre, the Salpetreire and Vaucluse. These physicians 
gave their judgments as to whether a case was an idiot, 
imbecile or higher grade. Binet says: "We have com- 
pared several hundreds of these certificates, and we think 
we may say without exaggeration that they looked as if 
they had been drawn by chance out of a sack" (77, p. 76). 

The rapid accumulation of data with psychological tests 
has made it possible to take our first halting steps in the 
direction of greater definiteness in diagnosis by a larger 
use of objective methods. This increase in significance 
of the concept of deficiency is fruitful at once in e stimating 
the size of the social problem and planning means for 
undertaking the care of these unfortunates- We can 
discover something of the error in the previous subjective 
estimates of the frequency of feeble-mindedness. We 
can bring together and compare the work of different in- 
vestigators, not only in our country, but throughout the 
world. We can discover, for example, how important the 
problem of deficiency is among different groups of delin- 
quents, knowing that the differences are not to be expfcrinpri 
by differences in expert opinion. Furthermore, we can 
now determine, with considerable accuracy, whether the 
diagnosis made by a reliable examiner is independent of 
his personal opinion. 

If we disregard the natural antipathy of many people 
to anything which tends to limit the charming vagueness 



FUNCTIONS OF A SCALE 13 

of their mental outlook, we may endeavor to chart this 
horizon of tested deficiency with something of the definite- 
ness of figures, which shall at the same time indicate a 
range of error. As soon as our aim comes to be to plot 
the borderline on a measuring scale of mental ability, we 
find that the borderline must be so stated that we can 
deal with either adults or children. Two sorts of limiting 
regions must be described, one for mature minds and one 
for immature minds. The latter will be in the nature of 
a prediction as to what sort of ability the children will 
show when they grow up. We must keep in mind, there- 
fore, that we should attempt our quantitative definition 
for both growing and adult minds. As soon as the grow- 
ing mind passes the lower limit for the mature it is then 
guaranteed access to the social seas although it may never 
swim far from shore nor develop further with advancing 
years. In seeking greater definiteness, our aim should 
then be to describe both the limit for the mature indiv- 
iduals and the limit for the immature of each age. In 
this paper the definition will be restricted to intellectual 
deficiency, i. e., tested deficiency. It will take the form 
of describing the positions on a scale below which fall the 
same lowest percentage of intellects. This percentage de- 
finition of intellectual deficiency offers such a simple meth- 
od of consistently describing the borderlines for mature 
and immature that it is surprising so little attempt has 
previously been made to work it out for a system of tests . 
Although the principle on which the definition is based 
depends upon the distribution curve of ability, it is con- 
cerned only with the lower limit of the distribution. Since 
the exact form of this distribution is uncertain I have pre- 
ferred to call it a percentage definition of intellectual de- 
ficiency rather than to state the limits in terms of the 
variability of ability. Moreover the lowest X per cent. 



14 DEFICIENCY AND DELINQUENCY 

in mental development requires no further explanation to 
be understood by the layman. 

B. Forms of Mental Deficiency Not Yet Dis- 
coverable by Tests. 

The first broad conclusion that impresses those who try 
to use mental scales for diagnosing feeble-mindedness is 
that the lower types, the idiots and imbeciles, can be de- 
tected with great accuracy by an hour's testing. The 
difficulties pile up as soon as the individual rises above 
the imbecile group. The practical experience of those in 
institutions for the feeble-minded here becomes of funda- 
mental importance. They are able to supply the history 
of exceptions that should make us cautious about our gen- 
eral rules. Certain people whom they have known for 
years to be unable to adjust themselves socially because 
their minds have not reached the level of social fitness will 
yet be able to pass considerably beyond the lower test 
limit for mature minds. The mental scales can only de- 
tect those feeble-minded who cannot succeed with our 
present tests. This is the basal principle in using any 
system of tests. 

Stated in another way, this first caution for anybody 
seeking the assistance of a mental scale is that tests may 
detect a feeble-minded person, but when a person passes 
them it does not guarantee social fitness. The negative 
conclusion, "this person is not feeble-minded,' ' can not be 
drawn from tests alone. Mental tests at present are 
positive and not negative scales. This fact will probably 
always make the expert's judgment essential before the 
discharge of a suspected case of mental deficiency. When 
a subject falls below a conservative limit for tested ability 
a trained psychologist who is familiar with the sources of 
error in giving tests, even without experience with the 



FUNCTIONS OF A SCALE 15 

feeble-minded, should be able to say that this person at 
present shows as deficient development as the feeble- 
minded. To conclude however that any subject has a 
passable mind requires in addition practical experience 
with feeble-minded people who pass the tests. It is very 
much easier to state that the tests do not detect all forms 
of feeble-mindedness than it is to give any adequate des- 
cription of the sort of feeble-mindedness which they do 
not as yet detect. 

This distinction between the feeble-minded who do well 
with test scales and those who do not, is well known in the 
institutions for the feeble-minded. Binet sought to 
distinguish some of the feeble-minded who escaped the 
tests by calling them ' 'unstable/ ' or ' 'ill-balanced/ ' in- 
dividuals as Drummond (77) translates the term. To use 
the historical distinctions of psychology, their minds seem 
to be undeveloped more on their volitional and emotional 
sides than on their intellectual side. Weidensall (59) has 
described another type as ' 'inert/ ' She found that quite 
a number of the reformatory women might slide through 
the tests but fail socially from the fact that ' 'their lives 
and minds are so constituted that they feel no need to 
learn the things any child ought to know, though they can 
and do learn when we teach them. ,, Again, it seems to 
be a disturbance of will through the feeling, rather than 
an intellectual deficiency. Many of the so-called "moral 
imbeciles' ' are probably able to pass intellectual tests last- 
ing but a few minutes. Like the unstable or inert they 
are not failures because of a lack of intellectual under- 
standing of right and wrong, but because of excess or de- 
ficiency of their instinctive tendencies especially in the 
emotional sphere. Such weakness of will may arise either 
from abnormality of specific instinctive impulses or in- 
ability to organize these impulses so that one impulse may 



16 DEFICIENCY AND DELINQUENCY 

be utilized to supplement or inhibit another. We may 
call all this group of cases socially deficient because of a 
weakness in the volitional, or conative, aspect of mind. 

The discrimination of mental activities which are pre- 
dominately emotional and conative from those in which 
intellect is mainly emphasized is also well recognized by 
those who have been making broad studies of tests in 
other fields than that of feeble-mindedness. Hart 
and Spearman {123), for example, call attention to 
the fact that tests passed under the stimulus of test con- 
ditions represent what the subject does when keyed up to 
it rather than what he would do under social conditions. 
We cannot be sure that speed ability as tested will repre- 
sent speed preferences. The subject may be able to work 
rapidly for a few minutes, but in life consistently prefer 
to work deliberately. Regarding the eighteen tests which 
they studied with normal and abnormal adults they say: 
'These tests have been arranged so as to be confined to 
purely intellectual factors. But in ordinary life, this 
simplicity is of rare occurrence. For the most part, what 
we think and believe is dominated by what we feel and 
want." Kelley (130) finds by the regression equation 
that the factor of effort amounts to two-thirds of the 
weight of that of the intellectual factor in predicting 
scholarship from teachers' estimates. Webb (217) thinks 
that he finds by tests a general conative factor comparable 
to Spearman's general intellective factor. 

With the change in point of view that has come from 
the adoption of the biological conception of the mind the 
discrimination of the different forms of feeble-mindedness 
must be recognized as a distinction in the emphasis on in- 
tellectual, emotional and conative processes, not a dis- 
tinction between actually separable forms of mental 
activity. On account of the organic nature of the mind 



FUNCTIONS OF A SCALE 17 

it is well established that various mental processes are 
mutually dependent. Any disturbance of the emotional 
processes will tend to affect the thinking and vice versa. 
Even if we believe that emotions are complex facts, in- 
volving vague sensations as well as feelings, and that terms 
like emotion, memory, reasoning and will are names for 
classes of mental facts rather than for mental powers, it 
still remains important to distinguish between feeling, 
intellect and will, as well as to recognize the interdepen- 
dence of the mental processes. Common sense seems to 
agree with psychological descriptions in regarding mind 
as a broader term than intellect, and feeble-mindedness 
as a broader term than intellectual feebleness. 

Since tests at present tend to reach the intellectual pro- 
cesses more surely than the emotional, we describe those 
who fail in them as intellectually deficient. The term 
"intellect" seems to be better than "intelligence" because 
the latter seems to include information as well as capacity, 
while the aim of measuring scales has been to eliminate 
the influence of increasing information with age. To be 
thoroughly objective, of course, one should talk about 
"feebleness in tested abilities;" but we would then fail to 
point out the important fact about our present scales that 
they detect mainly intellectual deficiency, that they do 
not reach those forms of feeble-mindedness in which the 
weakness in such traits as stability, ambition, perse- 
verance, self-control, etc., is not great enough to interfere 
with the brief intellectucal processes necessary for pass- 
ing tests. Intellectual deficiency will be used hereafter to 
refer to those social deficients whose feebleness is disclosed 
by our present test scales. 

In the opinion of Kuhlmann these cases of disturbed 
emotions and will which shade off into different forms of 
insanity should not be classed as feeble-minded at all, 



18 DEFICIENCY AND DELINQUENCY 

although he recognizes that they are commonly placed in 
this group. He regards them as an intermediate class 
between the feeble-minded and the insane. He says: 
'They readily fail in the social test for feeble-mindedness 
and because of the absence of definite symptoms of in- 
sanity are often classed as feeble-minded. In the opinion 
of the present writer they should not be so classed, because 
they require a different kind of care and treatment, and 
have a different kind of capacity for usefulness" {140). So 
long as this group of what we shall term "conative cases" 
is discriminated from the intellectually deficient it matters 
less whether they be regarded as a sub-group of the feeble- 
minded or as a co-ordinate class. In grouping them with 
the feeble-minded we have followed the customary classi- 
fication. An estimate of the size of this group will be 
considered later in Chapter III. 

C. Doubtful Intellects Accompanied py Delin- 
quency Presumed Deficient. 

Conative forms of feeble-mindedness are perhaps the 
most serious types in the field of delinquency. They are 
the troublesome portion of the borderland group of de- 
ficient delinquents about which there is so much concern. 
It is important to remember that it is just among these 
cases that the test judgment is least certain. In this 
dilemma one principle seems to be sound enough psycho- 
logically to be likely to meet with acceptance. I should 
state this principle as follows: .4 borderline case which has 
also shown serious and repealed delinquency should be classed 
as feeble-minded, the combination or doubtful intellect and 
repeated delinquency making him socially unfit. This will 
relieve the practical situation temporarily until tests are 
perfected which will detect those whose feebleness is spe- 
cialized in those phases of volition centering around the 
instinctive passions, control, balance, interest and endur- 



FUNCTIONS OF A SCALE 19 

ance. The principle recognizes that mental weakness is 
sometimes emphasized in the volitional processes of the 
mind. 

The principle is apparently in conflict with the rule 
advocated by Dr. Wallin. Referring to the mental levels 
reached by individuals, he says: "We cannot consider 
X-, XI-, or XH-year-old criminals as feeble-minded be- 
cause they happen to be criminals and refuse to consider 
X-, XI-, and XH-year-old housewives, farmers, laborers 
and merchants as feeble-minded simply because they are 
law abiding and successful" (214, p. 707). At another 
place he insists "that the rule must work both ways" 
(215, p. 74). Logically it would seem at first that it was a 
poor rule which did not work both ways. Further con- 
sideration will show, I believe, that there has been a con- 
fusion of feeble-mindedness with tested deficiency. If 
all the feeble-minded tested deficient intellectually then 
the tested level should determine whether or not they 
were feeble-minded. This, however, is not a correct 
psychological description of the facts. I prefer, therefore, 
to allow for those in a defined narrow range of weak in- 
tellects to be classed as deficient provided their weakness 
also manifests itself pronouncedly in the conative sphere. 

The principle that all mental deficients need not show 
the same low degree of intellectual ability is clearly recog- 
nized in perhaps the most important legal enactment on 
deficiency which has been passed in recent years, the Brit- 
ish Mental Deficiency Act of 1S13. It states regarding 
"moral imbeciles" that they are persons "who from an 
early age display some permanent mental defect coupled 
with strong vicious or criminal propensities on which 
punishment has had little or no deterrent effect." It 
specifically distinguishes them from the group of feeble- 
minded which require guardianship because of inability 
to care for themselves. 



CHAPTER III. THE PERCENTAGE DEFINITION 
OF INTELLECTUAL DEFICIENCY 

A. The Definition. 

In order to direct attention to the quantitative descrip- 
tion of intellectual deficiency which is here proposed, let 
us state the percentage definition in its most general form. 
Individuals whose mental development tests in the lowest X 
per cent, of the population are presumably intellectual- 
ly deficient, unless their deficiency is caused by remov- 
able handicaps. Above these is a group of Y per cent, 
within which the diagnosis of intellectual deficiency is 
uncertain on the basis of our present tests. The size of 
the presumably deficient X group is to be determined by 
the number of intellectually weak which society is at 
present justified in indefinitely isolating. The doubt- 
fully deficient Y group should include all those who are 
so intellectually deficient as to be expected to need as- 
sistance indefinitely. The feeble-minded, or mentally 
deficient, are those who require social care indefinitely 
because of deficiencyjn mental development. They include 
the X group, that portion of the doubtful Y group 
which is found to require isolation, guardianship or social 
assistance, and any others not detected by the tests but 
requiring prolonged social care on account of their failure 
to develop mentally. Under the principle which we stated 
at the close of the last section the combination of Y 
ability and persistent serious delinquency brings the case 
within the group presumed to be feeble-minded. 

Besides the greater definiteness and significance of such 
a definition of intellectual deficiency, it affords the simplest 
practical criterion for determining the borderline of pas- 
sable intellects with a scale of mental tests. A detailed 
comparison of the percentage plan with other forms of 

(20) 



PERCENTAGE DEFINITION OF DEFICIENCY 21 

quantitative definition will be found in Part Two. We 
may note here, however, that it guards against a number 
of the absurdities of current descriptions of the borderline 
with measuring scales. It is a criterion which may be con- 
sistently applied to the borderline of both the immature 
and the mature. It may be adapted with comparative 
ease to any system of tests. It aids in comparing the 
frequency of intellectual deficiency among different groups, 
for example, among different types of delinquents, re- 
gardless of whether the investigators have used the same 
series of tests, provided only that each series has been 
standardized for similar random groups. 

Any form of quantitative definition, on the other hand, 
involves certain assumptions which must be defended 
before it can claim to be of advantage for practical pur- 
poses. 

B. The Assumptions of a Quantitative Definition. 

(a) Deficiency is a difference in degree not in 
kind. 

Fortunately the tendency to describe the feeble-mind- 
ed person as if he were a different species from the normal 
has been definitely attacked by two noteworthy researches, 
that of Norsworthy (159) and that of Pearson and Jaeder- 
holm (164) (167). In these two investigations mentally 
deficient children either in special classes or in institutions 
have been compared with groups of normal children from 
the same localities on the basis of objective tests. The 
results are uniformly supported by numerous other studies 
of deficient and normal groups with the Binet and other 
tests. The conclusion is, therefore, thoroughly establish- 
ed that there is no break in the continuity of mental 
ability. It grades off gradually from average ability, and 
continually fewer and fewer individuals are to be found 



22 DEFICIENCY AND DELINQUENCY 

at each lower degree of ability. The borderline of de- 
ficiency will, therefore, not be a mental condition which 
clearly separates different kinds of ability, but a limiting 
degree of capacity to be decided upon by social policy in 
attempting to care for those who most need social guardi- 
anship. Since ability changes gradually in degree it is 
necessary to indicate a doubtful border region of degrees 
of ability on which expert judgment must supplement the 
test diagnosis. Below the doubtful region the diagnosis 
is c learly supported by objective test criteria, so that the 
on T y question to raise is whether the condition is caused 
by removable handicaps. The percentage definition 
thus strictly conforms to the best objective studies of 
mental deficiency in treating deficiency as a difference in 
degree. 

It should, perhaps, be said that this view is in direct 
conflict with the opinion that mental deficiency is ac- 
counted for as a Mendelian simple unit character. The 
opposing view has been advocated by Davenport (95, 
p. 310) and others in the publications of the Eugenics 
Record Office, and accepted by Goddard (112, p. 556). 
It has been so fully answered by Pearson (164) and Heron 
of the Galton Laboratory (127) and by Thorndike (198) 
that there is no occasion to take up the question in detail. 
We seem to be reaching an understanding so far as our 
present problem is concerned. If the explanation of the 
inheritance of mental ability is through Mendelian char- 
acters, nevertheless intellectual ability is the result of 
such a complex combination of units that it may best be 
thought of in connection with the unimodal distribution 
of ability adopted in this study. No random measure- 
ment of mental ability has ever shown any other form of 
distribution. 

The attempt has also been made by Schmidt (179) to 



PERCENTAGE DEFINITION OF DEFICIENCY 23 

find qualitative differences between normal and feeble- 
minded children by means of tests, and by Louise and 
George Ordahl (162) to find qualitative differences be- 
tween levels of intelligence among feeble-minded children. 
While these studies are very suggestive in pointing out 
the tests which most clearly indicate differences between 
individuals, they seem to me to fall far short of showing 
that the qualitative distinctions are anything more than 
larger quantitative distinctions. It is not clear that the 
authors intended them to mean anything more than this, 
so these studies do not seem to conflict seriously with our 
assumption that intellectual ability grades off gradually 
and uninterruptedly from medium ability to that of the 
lowest idiot. 

(b) AS TO THE VARIATION IN THE FREQUENCY OF DE- 
FICIENCY AT DIFFERENT AGES. 

A quantitative definition of intellectual deficiency 
would certainly be much simpler if it could be assumed 
that the percentage of deficients at each age is practically 
constant during the time when a diagnosis of deficiency 
is most important, say from 5 to 25 years. Otherwise the 
objection might be raised that it is impracticable to de- 
termine different percentages for each year of immaturity 
or to formulate our borderlines of ability for a particular 
age. When the general instinctive origin of intellectual 
deficiency is considered along with the incurability of the 
condition, we seem to be theoretically justified in assum- 
ing that the variation will be slight from one year of life 
to the next. This assumption is tacitly made by all 
those who use Stern's quantitative description of deficiency 
in terms of the mental quotient. On the other hand, 
there is a feeling among some of the investigators that 
there is a sudden influx of feeble-minded at particular 



24 DEFICIENCY AND DELINQUENCY 

ages and this position should be examined. Probably 
more important than this possibility of increase is the 
question of a decrease in frequency with age on account 
of the excessive death rate among the deficients. 

It is a natural supposition that there is a sudden in- 
crease in the proportion of feeble-minded at adolescence. 
On account of the increased rate of growth at this period 
we might expect to find greater instability for a few years. 
It may well be that there is a rather sudden influx of 
the unstable type of feeble-mindedness at this period. 
Such an increase may occur without being detected by 
a series of brief intellectual tests such as the Binet scale. 
It would be of the conative type of feeble-mindedness that 
cannot at present be diagnosed by objective tests, the 
type that requires diagnosis by expert opinion. It is to 
be noted, however, that Binet, who paid much attention 
to the unstable type, says: ' 'Since the ill-balanced are 
so numerous at ten years of age, and even at eight, we 
conclude that in many cases the mental instability is not 
the result of the perturbation which precedes puberty. 
This physiological explanation is not of such general ap- 
plication as is sometimes supposed' ' (77, p. 18). 

Only when an emotional disturbance is so great as to 
be detectable by mental tests will this influx need to 
be taken into consideration in stating the borderline for 
objective tests. The evidence that few cases of feeble- 
mindedness are not detectable until after ten years of 
age is all the other way. With the Stanford measuring 
scale, Terman and his co-workers did not even find a 
noticeable increase in the variability of the groups at the 
ages of adolescence (57, p. 555). It is to be remembered 
also that we are not concerned here with mere instability 
which corrects itself with more maturity, such as has been 
described by Bronner among delinquents. This does not, 



PERCENTAGE DEFINITION OF DEFICIENCY 25 

of course, amount to an incurable conative deficiency and 
is not classified under feeble-mindedness. 

Goddard has suggested that possibly the moral imbecile 
group comes into our class of feeble-minded suddenly 
with a common arrest of development at about the stage 
reached by the nine-year-old. He notes that "of the 
twenty-three cases of this sort picked out for us (at Vine- 
land) by the head of the school department, fifteen are in 
the nine-year-old group, five in the ten-year-old, two in 
the eleven, and one in the twelve' ' (113). He regards 
this evidence, however, as meager and only suggestive. 
Doll has given evidence of late appearance of retardation 
in rare cases (100 and 99). 

It is to be noted that if a sudden change is found in the 
percentage of children falling below a certain test standard 
it is perhaps more likely to mean that there is a change in 
the difficulty of the tests at that point. For example our 
Table V shows 1.3% of the nine-year-olds test two or 
more years retarded, while 18.9% of the ten-year-olds 
are retarded two years or more. This presumably indi- 
cates a change in the relative difficulty of the tests for 
VII and VIII rather than a change in the frequency of 
retardation at ages nine and ten. When we turn to God- 
dard's norms for VII and VIII we find that 81% of the 
seven-year-old children pass the norm for VII while only 
56% of the eight-year-old children pass the norm for 
VIII. 

The Jaederholm data (167) obtained by applying the 
Binet tests to pupils in the regular school classes and in 
special classes for the retarded may suggest a possible 
influx of intellectual deficiency at about 12 years of age 
or else "more mental stagnation in the intellectually de- 
fective' ' at this life-age and after. If one were to define 
intellectual deficiency in terms of the standard deviation 



26 DEFICIENCY AND DELINQUENCY 

of the regular school children, this data suggests that there 
is a marked increase in the number of children sent to the 
special classes at 12 years of age who are - 4 S. D. or lower. 
Roughly speaking it amounts to 36 children at 12 years of 
age, 36 at 13, and 21 at 14, as compared with 11 at 11 
years and 13 at 10 years. On the other hand, this may 
as well mean that intellectual deficiency becomes greater 
in degree rather than in frequency at these ages. The 
latter interpretation is adopted by Pearson for the Jaeder- 
holm data, so that it is perhaps not necessary to consider 
this evidence further. On the average the pupils in the 
special classes fall about .3 S. D. months further behind 
regular school children with each added year of life from 
5 to 14 inclusive. A third possible interpretation of the 
greater number showing the degree of deficiency measured 
by - 4 S. D. with the older ages should be mentioned. It 
is possible that 1 S. D. has not the same significance for 
5-year-olds as for 12-year-olds. The distribution of 
abilities at succeeding ages may be progressively more and 
more skewed in the direction of deficiency. We shall 
return to this point in Part Two as showing the advantage 
of the percentage definition over a definition in terms of 
the deviation. In connection with the Jaederholm data 
on special classes one should also consider the fact that 
younger children are not as likely to be detected by the 
teachers and sent to the special classes. It is possible also 
that the difference in difficulty of the tests for different age 
groups is somewhat obscured by using a year of excess 
or deficiency as a constant unit as Pearson has in treating 
this data. The bearing of this difference in difficulty 
was pointed out above for Goddard's data. 

The investigations by Pearson of children in the regu- 
lar school classes indicate that there is no important shift 
with maturity in the frequency of those with different 



PERCENTAGE DEFINITION OF DEFICIENCY 27 

degrees of ability, when the ability is measured either in 
terms of years of excess or deficiency with the Jaederholm 
form of the Binet scale or in terms of estimates of ability 
relative to children of the same age (166 and 167). In 
both these studies the correlation of ability with age was 
shown to be almost zero. For tested ability for 261 
school children "r" was .0105, P. E. .0417; with the esti- 
mated ability, the correlation ratios were for 2389 boys, 
.054, P. E. .014; for 2249 girls, .081, P. E. .014. Until 
we have better data this is certainly the most authorita- 
tive quantitative answer to the question of the shift with 
age in the frequency of the same relative degree of mental 
capacity. 

The best method of empirically settling this question 
of the early appearance and constancy of deficiency would 
be to test the same group of children again after they had 
reached maturity and find out how many of those who 
tested in the lowest X per cent, still remained in the same 
relative position. This is, of course, not possible at pres- 
ent, but it certainly should be done before we are dogmatic 
as to the permanent isolation of the lowest X percentage 
at any age. The nearest approach to this sort of evidence 
is Goddard's three annual testings of a group of 346 feeble- 
minded children with the Binet scale (117, p. 121-131). 
Among these 109 showed no variation, 123 gained or lost 
1 or 0.2 year, 18 lost 0.3 or more, and only 96 gained 
0.3 or more of a year. With so small a change in absolute 
tested ability the probability of a change in position rela- 
tive to normal children seems to be slight. Only one of 
the 76 who had tested in the idiot group gained as much 
as a half year in tested age in three years. 

It is not possible to settle this question of the constancy 
of the percentage of intellectual deficiency frbm one life- 
age to the next by considering the frequency of different 



28 DEFICIENCY AND DELINQUENCY 

ages of children among those who are sent to special 
classes for retarded pupils. This is evident from the fact 
that these classes contain a considerable proportion of 
those who are feeble mentally mainly because of conative 
disturbances. These would not be detected by our pres- 
ent tests and would not be classed as intellectually deficient. 
In the second place the pupils for the special classes are 
usually selected mainly on the advice of their teachers, 
who cannot, of course, without tests select those who are 
intellectually deficient except by trying them for a number 
of years in the regular school classes. This means that 
a smaller percentage of pupils in the special classes at the 
younger ages is to be expected. 

The figures of the U. S. Census as to the ages of inmates 
of the institutions for feeble-minded are also of little signi- 
ficance in connection with the question of the variation 
from age to age. That the number of inmates at the 
different ages is affected most largely by the pressure of 
necessity for shifting the care from their homes to the in- 
stitution is shown by the fact that three-fourths of the 
admissions are of persons over 10 years of age. It is also 
indicated by the fact that for the period from 15 to 19 
the males are over 20% more frequent than females, while 
from 30-34 the females are nearly 20% more frequent. 
Considering those ages most frequently represented in 
the institutions, 10-24 years, the average variation for 
the three five-year periods in the percentage of the popu- 
lation of the corresponding ages who are in these institu- 
tions is only 0.01%. The middle five-year period has the 
most, but even if there were a cumulation of feeble- 
mindedness with age, which is not shown, we would antici- 
pate a change of not more than 0.05% for these 15 years. 
This would be clearly negligible in considering the general 
problem. 



PERCENTAGE DEFINITION OF DEFICIENCY 29 

That little allowance for the variation from age to age 
need be made for the number of cases not discoverable 
at the beginning of school life is further indicated by re- 
port of the Minnesota State School for Feeble-Minded. 
It shows that in only 247 out of its 3040 admissions was 
the mental deficiency known to commence after six years 
of age (154). If the number of feeble-minded who should 
be isolated were found to increase after school age less 
than one in 10,000 of the population, as this suggests, it 
would surely be better to neglect this variation from age 
to age than to emphasize it in dealing with the problem 
of objective diagnosis and social welfare. 

How rare is the onset of feeble-mindedness after five 
years of age is also shown by the frequency of hereditary 
causes. In his study of the 300 families represented at 
Vineland, Goddard places only 19% in his "accidental" 
group and 2.6% in the group for which the causes are un- 
assigned. The rest are either in the hereditary group, 
probably hereditary, or with neurotic heredity. Half of 
the cases in the "accidental" group are due to meningitis. 
His histories show that only 9 of the "accidental" and 
unassigned groups were unknown at 5 years of age. This 
is only 3% of his total feeble-minded group. To these 
might be added, perhaps, a few from the hereditary groups 
who did not show their feeble-mindedness at sq early an 
age, but so far as I can judge these would not be of the 
intellectually deficient type that would be detectable by 
the Binet scale at any age. They would test high enough 
intellectually to pass socially and require expert diagnosis 
to be classed as feeble-minded. 

Certain diseases, epilepsy and meningitis, are undoubt- 
edly causes of feeble-mindedness. The evidence, how- 
ever, seems to be that they are so rare compared with 
the mass of mental deficiency that after 5 years they may 



30 



DEFICIENCY AND DELINQUENCY 



well be offset by the excessive death rate among the feeble- 
minded. That recoveries from feeble-mindedness are 
insignificant is generally agreed. Among the 20,000 in 
institutions in 1910 only 55 were returned to the custody 
of themselves. This is further evidence of the fundamen- 
tal, if not congenital, nature of the deficiency. 

While the evidence submitted above makes it seem fair 
to assume that the increase in the frequency of a certain 
degree of intellectual deficiency with age is probably 
negligible, it is not clear that the decrease with age in 
the proportion of feeble-minded caused by an excessive 
death rate may be neglected even for the test ages 5 to 25. 
By searching the literature it has been possible to assemble 
the records for nearly 3500 deaths among the feeble- 
minded in institutions in this country and Great Britain 
distributed by ages in ten-year periods. This evidence 
is presented in Table I. The number of cases under five 
years of age living in the institutions is so small that the 
deaths under five years are certainly misleading. They 
have, therefore, been omitted from the table and the dis- 
tribution calculated for those five years or over {123, 154, 
204, 205). Comparison is made with a similar distribu- 
tion of the total deaths for a period of five years from 1901 



Table I. Age Distribution of Deaths in the General Population and 
Among Feeble-Minded in Institutions. 



Population 








Ages 






Gen'l— U. S. 1,897,492 
in death registration 
area 


5-14 
6.1% 

26.6 


15-24 
9.6% 


25-34 
12.8% 


35-44 
13.0% 


45-54 
13.6% 


55 & over 

44.9% 


F. M. 1910 in 
Institutes in U. S. 840 


33.0 


18.9 


9.1 


45 & over 
12.3 

3.5 




F. M. British 
'Earlswood) 997 


34.3 


41.1 


10.4 


6.5 


55 & over 
4.2 


F. l M. British 

(Barr) 613 


34.7 


46.8 


9.5 




35 & over 
9.0 




F. M. Faribault 
Minnesota 982 


27.6 


38.0 


16.1 


8.6 


3.5 


55 & over 
6.2 



PERCENTAGE DEFINITION OF DEFICIENCY 



31 



to 1904, inclusive, within the area of the United States 
in which deaths are registered, compiled from the special 
mortality report of the Bureau of the Census (206). This 
registration area has a population of about 32,000,000. 
The general agreement of the distribution of deaths among 
the four different groups of institutional inmates seems to 
make it reasonable to assume that the United States 
group of institutional deaths for the year 1910 is a con- 
servative description of excessive death frequency at the 
early ages among the feeble-minded in institutions. 

A comparison of the death rates of the feeble-minded 
and the general population at different ages is of prime 
importance in connection with all attempts at quantita- 
tive descriptions of deficiency. Heretofore this has been 
completely neglected. Fig. 1 and Table II have been 
prepared to provide a roughly adequate estimate, on the 
basis of the above data for the United States, as to the 
survival of 1000 institutional cases of feeble-minded 5 
years of age for successive age periods compared with 
1000 people in the general population. In constructing 
this table it was necessary to assume, since the facts were 
not given, that the age distribution in the registration 
area of the general population was the same as for the 
United States as a whole (census of 1910) and that the 
number of feeble-minded in the institutions at the various 
age periods was equal to the number enumerated on the 
first of January plus the admissions during the year 1910, 



Table II. Mortality of Institutional Deficients in the United States 
Compared with the General Population, Showing its Possible Effect on 
the Frequency of Deficiency at Different Ages. 

Ages 





5 

1000 
1000 


10 
983 
795 

1.11 


15 


20 


25 


30 
903 


35 


40 


General population 


972 
696 

1.00 


956 
606 


934 


872 
349 


835 


Deficients in Institut'ns 


503 
.75 


428 


290 


Per cent deficient if 1 % 
at age 15 


1.40 







32 



DEFICIENCY AND DELINQUENCY 



fUUU 


\ 




-Gsag, 


/ 








900 


\ 

\ 
\ 






^-^ 


^ 


s> 




\ 

\ 














600 


\ 
\ 
> 












S 
















700 




% 
































\ 


&> 
















\- 








Soo 








\ 


V 




















400 


























\ 
\ 
\ 




•| 300 














N 














> 


*0 zoo 






























5 /oo 

n 













































5 10 15 20 25 30 35 40 

Age 

Fig. 1. Mortality among Feeble-Minded in Institutions Compared With 
the General Population 



PERCENTAGE DEFINITION OF DEFICIENCY 33 

disregarding the number discharged since they are not 
distributed by ages. The average annual death rate 
among the institutional cases of feeble-minded 5 years 
of age and over in the United States in 1910 was 35.19 
per thousand, while the corresponding death rate in the 
general population of the registration area for the five 
years 1901-1904 inclusive was 13.56. Assuming that 
the death rates are uniform within the five-year periods, 
the decline in the proportion of institutional feeble-mind- 
ed from 5-25 years of age as the result of excessive mor- 
tality is indicated by the last line in Table II, after allow- 
ing for the mortality in the general population. That 
this effect of excessive mortality upon the percentage of 
feeble-minded cannot be neglected between 5 and 25 
years of age is apparent unless the mortality among in- 
stitutional cases is much greater than it is among the 
deficient generally. As the figures stand the proportion 
of feeble-minded would be reduced nearly one-half be- 
tween ages 5 and 25. Only a small part of this reduction 
probably would be compensated for by new cases develop- 
ing from accident or disease. On the other hand there is 
little doubt that the institutions contain an excessive 
proportion of low grade cases among whom the mortality 
is much greater. The mortality among institutional 
cases is, therefore, probably not typical of that among the 
feeble-minded generally. Nevertheless it is so great 
that any quantitative definition of deficiency which ne- 
glects it entirely is open to serious objection. We shall, 
therefore, keep this variation in mind in connection with 
the discussion in the next chapter of the percentage which 
is deficient, and in the adaptation of the definition to a 
measuring scale. It is clear that the percentage should 
be so chosen as to allow best for the possible large effect of 
excessive mortality among the deficients. Finally, it 



34 DEFICIENCY AND DELINQUENCY 

should be said that the percentage definition of feeble- 
mindedness might be modified to meet a varying percent- 
age from age to age should that ever become desirable. 

(C) AS TO THE NUMBER OF DEFICIENTS NOT DETECTED 
BY TESTS. 

If most of the feeble-minded for whom society should 
provide were of the type which is only conative and not 
detectable by our present objective tests, a quantitative 
definition would be abortive. We must, therefore, study 
our assumption that it is worth while to direct our at- 
tention to those who are intellectually deficient. We 
shall attempt to discover how frequent are the primarily 
conative types. 

Before examining the quantitative evidence we may 
note that it is in conformity with two prominent recent 
tendencies in psychology to subordinate specialized abil- 
ities, as compared with abilities which function commonly 
in many situations. The first of these tendencies is 
represented by the fundamental researches of Hart and 
Spearman (123) (185). This is not the place to set forth 
the technical work on which their conclusions are based. 
It may be said, however, that, with 17 different psycholog- 
ical tests, they were unable to discover any important 
specific mental weakness which distinguished adults who 
were suffering with any one of various mental abnormal- 
ities, including imbecility, manic-depressive insanity, 
dementia praecox, paranoia, and general paralysis of the 
insane. This may have been the fault of the tests, but 
it seems to be more likely that the fault lies in the custom 
of emphasizing special abilities and disabilities, at least 
from the point of view of tested capacities. On the other 
hand, all of these mental abnormalities showed a weak- 
ness in general intellectual ability. This is true whether 



PERCENTAGE DEFINITION OF DEFICIENCY 35 

this general ability be regarded, as it is by Hart and Spear- 
man, as due to a general fund of brain energy, or whether 
general ability be taken to refer to the common recurrence 
of many specific abilities in much of our mental life. Its 
significance for this study is that a series of varied tests, 
such as that of Binet, may be expected to give a good es- 
timate of general ability, and its failure to disclose speci- 
fic disabilities is thus less important. 

The second influence in psychology tending to empha- 
size average tested ability is the establishment of the bio- 
logical conception of the mind which recognizes the mutual 
interdependence of the mental processes, organically 
united through the activity of the brain. So long as in- 
tellectual, emotional and volitional processes are all 
mutually dependent, a disturbance of one aspect of mental 
life is bound to affect the others. In considering the mu- 
tual dependence of the mental processes, it is important 
to weigh carefully the striking examples which Bronner* 
has brought together, illustrating special abilities and 
disabilities. She has made an admirable start toward a 
differential diagnosis of special defects in number work, 
language ability and other mental activities. The degree 
of special deficiency which results in social failure could 
be placed upon an objective basis, but the rarity of special 
deficiencies as compared with general deficiency will make 
this a slow task. In the meantime we may rely upon the 
mutual dependence of the organic processes as a point 
of view which emphasizes the common spread of deficiency 
to many activities. Knowledge of a single case of specific 
disability is sufficient to make us recognize that such 
cases do occur. On account of the rarity of those cases 
and the absence of objective criteria, it seems necessary 

* Augusta F. Bronner. The Psychology of Special Abilities and 
Disabilities. Boston, 1917. Pp. vii, 269. 



36 DEFICIENCY AND DELINQUENCY 

to leave the further differentiation to the future, consider- 
ing here only those cases which may be grouped together 
as conative, as contrasted with those detected by our gen- 
eral intellectual tests. 

Whether the group of primarily conative cases is of any 
considerable size can be only very roughly estimated at 
present, since the diagnosis of such cases of feeble-mind- 
edness rests at present almost exclusively on the subjective 
opinion of the examiner. Before their diagnosis is put 
upon an objective basis we must have a different form of 
test directed at such traits of will as initiative, persever- 
ance, stability and self-control. These probably center 
on the mental side around the instinctive emotional back- 
ground of interest and the passions, while, on the physical 
side, they raise the question whether the subject's energy is 
adequate to endure the strain of competition or whether 
it shows itself only in sudden bursts. 

If the diagnosis of conative cases could be determined 
objectively, it is possible that most forms of social unfit- 
ness would be found highly correlated with intellectual 
deficiency. On the other hand, when the diagnosis of 
unfitness for school or social life depends merely upon the 
opinion of experts or teachers, the inaccuracy of the diagno- 
sis may show a wide discrepancy between the so-called 
conative and intellectual types of deficiency. Binet, on 
the basis of his acquaintance with the pupils in special 
classes, suggested that the number of unstable children 
is probably equal to the number of those who are intel- 
lectually unsuited for the ordinary schools or institutions 
(77). Since he then places the total number of the two 
classes at four or five per cent., it is apparent that he is 
discussing a higher type of ability than is usually included 
under the term feeble-minded. We can get somewhat 
better evidence on this question by studying the results 



PERCENTAGE DEFINITION OF DEFICIENCY 37 

of Binet tests applied to children cared for in special classes 
or in institutions for the feeble-minded. Chotzen (90) 
presents a table of 280 children in the Hilfsschule in Bres- 
lau, only 201 of whom, however, he himself diagnosed as 
feeble-minded, i. e., debile or lower. Of these only 51 
were intellectually deficient as indicated by the Binet 
tests when we include the doubtful cases according to the 
criteria we have adopted in this study. If we suppose 
that, in addition to those in the special classes, there would 
be one intellectually deficient child in an institution for 
feeble-minded for every child testing deficient, we would 
then guess that only 40% of the feeble-minded children 
in Breslau were intellectually deficient. This sort of 
estimate seems to agree with Binet's belief that half of 
the children requiring special care, at least during school 
ages, are cases which are primarily conative. 

Pearson has approached the same problem in another 
way (164) (167). He has used the results of the psy- 
chological tests applied by Norsworthy to children in New 
York in special classes and institutions for feeble-minded 
compared with those in the regular school classes, and the 
results of Jaederholm obtained with the Binet tests applied 
to 301 children in Stockholm in the special classes compar- 
ed with 261 others selected from the regular classes. He 
found that '70.5% of normal children fall into the range 
of intelligence of the so-called mentally defective; and 
60.5% of so-called mentally defective children have an 
intelligence comparable with that of some normal children' ' 
(167, p. 23).' On the statistical assumption that those in 
the normal classes would distribute according to the Gaus- 
sian normal probability curve he estimates that, with the 
Binet tests, among those in the special classes "10% to 
20%, or those from 4 to 4.5 years and beyond of mental 
defect, could not be matched at all from 27,000 children' ' 



38 DEFICIENCY AND DELINQUENCY 

(164, p. 46). Another 20 to 30% could be intellectually 
matched by those in the regular classes having from 3 to 
4.5 years of mental deficiency, but they would be matched 
very rarely. On the assumption that 1% of the children 
were feeble-minded, not more than about two children in 
a thousand of this regular school population would be 
expected to be 3 or more years retarded and thus overlap 
those of like deficiency in the special classes (167, p. 30). 
Considering the results of Norsworthy's study he says on 
similar assumptions: "It seems, therefore, that a care- 
fully planned psychological test, while not sufficing to 
differentiate 50 to 60% of the mentally defective from 
the normal child, would suffice to differentiate 40 to 50%' • 
(164, p. 35). Again we come back to the estimate 
that psychological tests may well be expected to select 
nearly half of the children at present found in special clas- 
ses for retarded pupils. Moreover, a considerable part 
of the overlapping of intellectual deficiency in the regular 
classes with that in the special classes which he found may 
be accounted for by the inadequate methods of selection 
of pupils for the special classes by teachers or examiners 
who have used no objective tests. Some who were left in 
the regular classes should undoubtedly have been trans- 
ferred to special classes and vice versa. There seems to be 
nothing to indicate that less than half of those properly 
sent to special classes would be of clear or doubtful intel- 
lectual deficiency. If the tests served to select even a 
smaller proportion of those assigned to special instruction, 
the "school inefficients ,, as Pearson calls them, their value 
as an aid to diagnosis would be demonstrated. 

Among groups of delinquents, where we would expect 
the purely conative cases to be more common, we find 
that a careful diagnosis of feeble-mindedness on the basis 
of test data, medical examination and case history indi- 



PERCENTAGE DEFINITION OF DEFICIENCY 39 

cates that conative cases without serious intellectual de- 
ficiency are much rarer than intellectually deficient de- 
linquents. At least this is the evidence of one study 
where such information is available. Kohs at the Chica- 
go House of Correction found among 219 cases over 16 
years of age, which he diagnosed as feeble-minded, only 
28 tested XI and there were only 52 who did not test 
either presumably deficient or uncertain intellectually 
according to our criterion. Another bit of evidence is 
that collected at the Clearing House for Mental Defectives 
in connection with the New York Post-Graduate School of 
Medicine, where 200 consecutive cases (108 males) were 
examined by Miss Hinckley. Her graphs show that only 
15% tested X or above with the Binet revised scale, i. e., 
above those presumably deficient in intellect. The cases 
were from 13 to 42 years of age. The clearing house pro- 
vides an opportunity for social workers to have suspected 
deficients examined and the few cases over X seems to in- 
dicate that the purely conative type is not very commonly 
met with among the social workers. 

When we turn to the institutions for the feeble-minded 
we find that they are today caring for few solely conative 
cases. Although I can find no tables which give both 
the life ages and mental ages of the individual inmates, we 
can at least be sure that few test so high as X, or above 
with the Binet scale. This means that only a few have 
as yet reached the threshold for passable adult intellects, 
which should be attained by 15 years of age. At the 
Minnesota state institution for the feeble-minded in Fari- 
bault among 1266 inmates, excluding epileptics, 41 tested 
X; 28, XI; 12, XII; and 8, XIII, a total of 7% (154). 
At Vineland, N. J., Goddard reported among 382 inmates, 
14 tested X; 5, XI; and 7, XII, about 7%. Some of the 
children who were under 15 in life-age might later develop 



40 DEFICIENCY AND DELINQUENCY 

above the limit for intellectual deficiency. Of the 1266 
at the Minnesota institution, however, 508 were 15 or 
over at the time of their admission, so that at least 82% 
of the 508 were clearly intellectually deficient. Eight 
per cent, more tested X and were in the doubtful group 
in intellectual ability according to the criteria we have 
adopted. This suggests that not more than about 10% 
of those who are at present isolated in institutions are 
there for feebleness of will alone. It seems to confirm our 
presumption that the intellectually deficient discovered 
by tests form the great majority of the social deficients 
who need prolonged care or assistance. 

(d) Allowance may be made for variability. 

The quantitative definition of intellectual deficiency 
must be made with careful allowance for irregularities 
among different mental processes, among different in- 
dividuals, and among different groups. Theoretically 
it is possible to place the borderline so low that a case with 
that degree of deficiency and without removable handi- 
caps would be clearly feeble-minded. The chance that 
the diagnosis would be mistaken could be reduced to any 
minimum desired. Above this a wider region of doubtful 
deficiency could then be stated in similar form. This is 
the plan that we suggest in attempting the percentage 
definition. Practically, however, the plan assumes that 
a suitable allowance can actually be made for these var- 
iations and raises a number of problems as to variability 
which should be considered. Four of these sources of 
variation are discussed below: (1) the variation due to a 
limited sample of individuals measured, (2) the variation 
among different communities, (3) the variations arising 
from sex, race and social differences, (4) the variation of 
the same individual from one mental process to another. 



PERCENTAGE DEFINITION OF DEFICIENCY 41 

We do not have the problem of neglecting these variations, 
but of adequately allowing for them both in the percentage 
of presumably deficient and in the doubtful region. 

(1) Variation among Samples of Individuals Measur- 
ed. The error introduced by the fact that measurements 
are made on a limited rather than an unlimited number 
of individuals, in establishing the standards with a system 
of tests, can be taken care of statistically fairly well by 
applying the theory of probability as to the error of a 
percentage in a single sample. The range of the error 
can then be indicated on the measurement scale. This 
supposes, however, that each sample to be measured is 
taken from a random group and not from a selected group. 
Allowance for this error of sampling is therefore compli- 
cated by the fact that the usual test data have been ob- 
tained from groups of school children, even when there 
has been no further selection within the school group. 
Data on school children are certainly reliable only within 
the years of compulsory school attendance. Ordinarily 
in this country, they are not reliable for children of 14 
years of age or over. Moreover, the point of the scale 
which is reached by the lowest X percentage of school 
pupils will exclude a slightly larger percentage of all chil- 
dren of corresponding ages, since the idiots and some im- 
beciles are not sent to the ordinary schools. This slight 
discrepancy should be kept in mind. The problem of 
avoiding selected samples among adults is still more diffi- 
cult; but we found that it was possible in one community 
at least to measure all the 15-year-olds in the lowest X 
percentage in certain districts, as we shall note later. By 
this age, mental processes are probably very much like 
those of adults, except for the amount of information 
and practise. 



42 DEFICIENCY AND DELINQUENCY 

(2) Variation among Different Communities. Under 
any conception of deficiency it is clear that there are rela- 
tively more deficients in some communities than others. 
The percentage should, of course, not be determined for 
a small community such as a city or county, but for a 
state or a nation in order to avoid the difficulty of the differ- 
ence between communities. It would not interfere with 
the plan for isolating the lowest X percentage of a state 
even if that meant isolating 10% in one small community 
and none in another. Indeed, it might be expected to do 
just that, when one considers the accumulation of deficiency 
in certain settlements such as Key has shown (131, p. 63). 
The data on which the borderline with a measuring scale 
would be established should, of course, not be obtained from 
communities known to be unusual in respect to the 
frequency of deficiency. 

Since social failure is our final criterion for judging de- 
ficiency, we must further consider that it is easier for a 
person to survive in one environment than in another: 
in the country, for example, than in the city. This sort 
of problem has led to considerable confusion. Goddard 
remarks: "In consequence of this it happens that a man 
may be intelligent in one environment and unintelligent in 
another. It is this point which Binet has illustrated by 
saying 'A French peasant may be normal in a rural com- 
munity but feeble-minded in Paris/ " (117, p. 573.) 
Goddard then goes on to suppose that a delinquent with 
the intelligence of a sixteen year old may be ' 'defective' ' 
because he happens "to have got into an environment 
that requires a twenty-year-old intelligence/ ' The sug- 
gestion that a criminal might be excused on the ground 
of deficiency because he happened to fall among bad 
companions is a reductio ad absurdum. Clearly environ- 
ment must be defined as ordinary environment, available 



PERCENTAGE DEFINITION OF DEFICIENCY 43 

environment or by some similar concept, or else the defin- 
ition of deficiency loses all significance. In another place 
Goddard more properly suggests that it would be well to 
"draw one line at that point below which a person of that 
intelligence is not desirable or useful in any environment" 
(117, p. 3). 

So long as the care of the feeble-minded is a state prob- 
lem the percentage of passable intellects would apparently 
be determined for the available environment in that state. 
The problem of social care cannot mean that the state 
should care for college men because they cannot survive 
among college men or in the station of life into which they 
may have been born. So long as there are environments 
within the community where they can survive it is a 
problem of shifting them in their social habitat, not a 
problem for social care. The same is true for the low 
grades of intellect. It is not likely, however, that any 
portion of the community could absorb many more of the 
low degree intellects. For the problem of social care for 
the feeble-minded, the question: What environment will 
allow this individual to survive? becomes the question: 
Can he survive in any available environment in his com- 
munity? It would seem very hazardous to suppose that 
the different opportunities for survival afforded by differ- 
ent localities in a state would be large enough to care for 
more than the group of doubtful cases which should be 
allowed for in a quantitative description of the border 
region. 

(3) The Variation with Sex, Race, and Social Position 
has been carefully called to attention by Yerkes and 
Bridges in their studies with the Binet Point Scale (225, 
Chap. V and VI). It may very well be that not as high 
ability should be expected of certain groups as of others; 



44 DEFICIENCY AND DELINQUENCY 

as a matter of moral obligation, they are not as responsible 
for their conduct or their attainments. On the other 
hand this does not directly affect the question, what low- 
est percentage of intellects cannot get along in society? 
When that percentage is determined for the environment 
available in the community all those who fall within it 
might even turn out to be of one sex or of one nationality 
or of one social position, without affecting the question 
whether they should be cared for by society, or what 
grade of intellect is not socially passable? Temporary 
social handicaps, such as lack of familiarity with the 
language, lack of training, etc., must, of course, be allow- 
ed for so far as they affect the individual's test record. 
Whether the difference of 5% to 10% in the score of 
pupils born to non-English-speaking families compared to 
their companions' {225, p. 66) is due to the temporary 
handicap of language or to a permanent difference is, how- 
ever, just the problem which the Yerkes and Bridges study 
does not answer. The fact that the difference is even 
greater for older children suggests that it may indicate 
an inborn difference between the groups compared. 

A diagnosis of deficiency should not be made until the 
examiner is able to estimate whether the removal of train- 
ing or health handicaps would bring the individual above 
the borderline. So far as known temporary handicaps 
affect the standard of the test results with groups they 
should, of course, also be taken into account. On the 
other hand, it is clear that the borderline which predicts 
social failure should not be shifted to allow for differences 
in permanent handicaps whether those be of race, sex or 
social position. 

(4) The Variation among Different Mental Processes. 
With our present knowledge the most difficult variation 
for which we must make allowance at the borderline is the 



PERCENTAGE DEFINITION OF DEFICIENCY 45 

variation from one trait or process to another in the same 
individual. One phase of it was discussed above under 
"c." The investigation of Norsworthy throws light on 
this question. Summarizing her tests she says: "Among 
idiots there is not an equal lack of mental capacity in 
all directions. There is something of the same lack of 
correlation among the traits measured in the case of idiots 
as there is with ordinary people" (159, p. 68). Again: 
"The idiots are nearest the central tendency for children 
in general in the measurements of mental traits which 
are chiefly tests of maturity, and farther and farther 
away as measurements are made which are tests of ability 
to deal with abstract data. They are two and a half 
times as far from the median for children in general in tests 
like the genus-species test as they are in tests like the A 
test or the perception of weight." Weidensall (60) and 
Pyle (46) also compare delinquent and normal individuals 
for different tests, showing a variation with the sort of 
mental activity compared. 

While Norsworthy thus presents evidence of certain 
specializations of deficiency, she notes, however, that 
perhaps feeble-mindedness is more typically general than 
specific and that general deficiency is more important to 
consider than specific. Even with that test with which 
her group of retarded and feeble-minded children did best, 
only 28% of them passed the point which would be ex- 
celled by 75% of the children in general. In their worst 
test only 1% passed this point. It is also to be noticed 
that those tests in which they most nearly approached 
ordinary children are for just those simple processes which 
would be least likely to be of use in the struggle for social 
existence. As a whole, therefore, there is nothing in her 
results which shows that any appreciable number of chil- 
dren who were deficient in the average of tested abilities, 



46 DEFICIENCY AND DELINQUENCY 

would have good enough special ability along a few lines 
to make them socially passable. Indeed, for all that we 
know at present, the borderline for passable ability in each 
of our various mental processes might vary quite as much 
as Norsworthy found, without this variation affecting a 
prediction of failure based upon the average of a series of 
tests. 

On account of the great attention that has been paid 
to individual differences in recent years, on account of 
their importance for diagnosis, for determining the causes 
of deficiency, and for planning for the training of deficients, 
we have come almost to the point where we forget the 
significance of the average as the most common condition 
with which we have to deal. The lack of complete cor- 
relation between abilities of an individual does not make 
us hesitate to use the concept of his average ability; it 
should not make us neglect or misunderstand the signi- 
ficance of the position of an individual testing low down 
on the scale. For the problem of social care the border- 
line position on a scale is immensely more important than 
higher ability. It seems advisable, therefore, to define 
this borderline ability with some suitable allowance for 
variability in mental processes. It is far safer to judge an 
individual's chance of survival by his average or general 
tested ability than by the little knowledge that is as yet 
available regarding special abilities. 



CHAPTER IV. WHAT PERCENTAGE IS 
FEEBLE-MINDED 

A. Kinds of Social Care Contemplated 

At first it seems like a hopeless task to try to bring har- 
mony out of the confused estimates of the proportion of 
the feeble-minded in modern society. Authoritative 
estimates by commissions or by recognized experts range 
from less than 0.2% to 5.0% that is, from 2 to 50 per 
thousand. Further study of these estimates shows that 
they reflect not so much a difference in expert opinion 
about the same problem as differences in the problems 
which were considered in making the estimates. As soon 
as we compare only those estimates that have been made 
to answer the question, what percentage of low grade minds 
should be provided with a certain form of social care? it is 
rather surprising how much less the discrepancy becomes. 
An analysis of important estimates will therefore be under- 
taken in order to try to discover some of the sources of dis- 
agreement. 

The most significant thing about an estimate is that 
the estimator is thinking of providing for his group of 
deficients in a special way. This is the purpose of the 
estimates. Three important groups of the mentally de- 
ficient now demand attention. They are: (1) The group 
which, for moral and eugenic reasons, society is justified 
in isolating for life or an indefinite period. (2) The group 
which needs special simple industrial training in order to 
get along with social assistance without isolation. These 
deficients may be cared for in their home towns by special 
schools, public guardians, and after-care committees. 
(3) The group which needs special school assistance, but 
is socially passable after leaving school. These individu- 
als are incapable of competing in school with their fellows, 

(47) 



48 DEFICIENCY AND DELINQUENCY 

but they are able to get along in the simplest employments 
without social assistance. We may designate these three 
groups as those needing (1) social isolation, (2) social 
assistance, and (3) only school assistance. The largest 
estimates of feeble-mindedness, it will be found, include 
the third group, while the smallest intend to include only 
the first group. The first and second groups are clearly 
below the limit of feeble-mindedness designated by the 
verbal definition of the British Commission. They are 
socially unfit. The language of that definition is ambig- 
uous enough to include the third group, but the plan of 
the Commission, judged by its consideration of the num- 
ber to be sent to special schools, would regard only the 
first two classes as feeble-minded. Following this common 
conception I have regarded those in the third group as 
above the feeble-minded. It will help to find harmony 
among the estimates if we estimate separately those men- 
tally deficient enough to need social isolation, social as- 
sistance, and only school assistance. This discrimina- 
tion of the retarded by the kind of social care needed 
should also make the social definition more useful. 

B. Estimates of the School Population Versus 
the General Population 

Before we consider the percentage estimates in detail 
for these different forms of social care, let us note the 
effect on them of two other considerations. The first of 
these is the discrepancy between estimates of the pro- 
portion of feeble-minded among school children and 
estimates as to the proportion in the general population. 
Since feeble-mindedness is regarded as a permanent arrest 
of mental development occurring at an early age and us- 
ually due to hereditary causes, it is plain that a school 
child who is feeble-minded would be expected to remain 



PERCENTAGE INTELLECTUALLY DEFICIENT 49 

so for life. Nevertheless we find that estimates of 0.3% 
of the general population are accompanied by estimates 
of 1.0% or 2.0% of the school population as feeble-minded. 
I have not been able to find any careful attempt to account 
for these discrepancies. The excessive mortality among 
the feeble-minded is hardly adequate to explain so great 
a difference. 

It is interesting to note some of these comparisons. 
Goddard, for example, considers it conservative to esti- 
mate that 2% of the school population is ' 'feeble-minded' ' 
{112, p. 6). In the same publication he says: 'There 
are between 300,000 and 400,000 feeble-minded persons 
in the United States" (p. 582). Since the elementary 
school enrollment is about 20,000,000 {208), the feeble- 
minded school children alone on his first estimate would 
account for 400,000 feeble-minded in the United States 
without allowing for any feeble-minded outside of the 
ages in the elementary school. 

The report of the British Royal Commission, published 
in 1908, forms the starting point for many of the esti- 
mates made today. The commission added together the 
number of school children which were thought to require 
special classes with the number of defectives found in 
institutions, prisons and almshouses, or reported by its 
medical investigators. The total gave 0.46% of the gen- 
eral population as "mentally defective persons," not in- 
cluding certified lunatics. From this amount should be 
deducted .06% who were insane but had not been certi- 
fied as such, leaving 0.4% mentally deficient. This was 
not regarded by the Commission as an estimate, but was the 
number actually "enumerated by the medical investiga- 
tors" in sixteen typical districts studied in England and 
Wales with a total population of 2,362,222 {83, VIII, 
p. 192). Turning to the school children we find that in 



50 DEFICIENCY AND DELINQUENCY 

the areas investigated there were 436,833 school children 
of whom 0.79% were found defective. Since this was 
an enumeration and not an estimate, the commission paid 
no attention to the discrepancy between 0.79% of the 
school children and 0.31 % of the rest of the population. 
Tredgold, moreover, based his estimates of the frequency 
of the mental deficiency in England and Wales on the data 
of the Royal Commission without attempting to harmon- 
ize this discrepancy. This oversight has apparently been 
one source of the not uncommon difference between the 
estimates for school children and for the general popula- 
tion. One suspects that the fact that the elementary 
school population is about a fifth of the general popula- 
tion, has also mistakenly contributed to this error. The 
discrepancy of three to five times as large a frequency 
of deficiency among school children as in the general 
population certainly needs clearing up. 

There is an escape from this dilemma which seems more 
reasonable than to attempt to account for the discrepancy 
by excessive mortality. When estimates are made con- 
cerning the school population the estimator is usually 
thinking of that group of feeble-minded which needs 
special school training and probably social assistance after- 
ward. When estimates are made of the general popula- 
tion the estimator is likely to be thinking of that group 
which must be cared for permanently by society, mainly 
in institutions or colonies. For some time at least the 
state cannot be expected to undertake the indefinite care 
of all the deficients who should have, at once, simple in- 
dustrial training, in special local schools or classes in or- 
der to survive, even with social assistance. This differ- 
ence in the type of care contemplated seems most naturally 
to account for the discrepancy found with many writers, 
between their estimates for the school population and for 
the general population. 



PERCENTAGE INTELLECTUALLY DEFICIENT 51 

C. Desirable Versus Immediately Advisable 
Social Care 

A second source of confusion arises when one investi- 
gator is thinking of the number of feeble-minded, the care 
of whom it is desirable that society should assume, and 
another is thinking of the feeble-minded, the care of whom 
it is advisable for society to assume at once. Considered 
in connection with a specific case -the distinction is quite 
obvious. It is one thing to say that it would be desirable 
for the state to assume the indefinite care of a particular 
person, it is quite another thing to say that it would be 
advisable for the state to assume that care immediately, 
when one remembers the crowded condition of the in- 
stitutions, the necessity of caring for the worst cases first, 
the possibility of the person being cared for by his own 
family or in a local school, the added public expense, the 
necessary neglect of other movements for social welfare 
if society assumes this expense, etc., etc. 

When you magnify this problem in the mind of the 
estimator who is interested in the question of caring for 
the groups of feeble-minded, the result is that his esti- 
mates of the size of the groups are decidedly affected. 
For example, few would deny that the Site Commission 
of New York appointed to locate the colony for mental 
defectives, now known as the Letchworth Village, was 
emphasizing a program of permanent social care when 
it estimated the number of feeble-minded in New York. 
The Commission, "after taking into consideration the 
figures of the State and National census, and other data 
collected from institutions/ ' estimated that there were in 
New York state possibly 12,300 mentally defective per- 
sons" (Editor's Note, 205, p. 84). This is less than 0.15% 
of the population and very low compared with most esti- 
mates. 



52 DEFICIENCY AND DELINQUENCY 

The low estimates will generally be found to be influ- 
enced by considerations of public expense rather than the 
social unfitness of the lower group. Inasmuch as there 
are no sharp distinctions between different degrees of 
mental ability this consideration of public expense is per- 
fectly proper. At the other extreme, however, are the 
eugenists who are convinced that it is desirable to isolate 
a large group at the lower range of ability. The member of 
the legislature will be concerned mainly with the question 
how much money will the public be willing to appropriate 
now for the care of these unfortunates. The eugenist 
will be thinking of an ideal rather far in the future to- 
wards which to work. 

The diagnostician should take a conservative inter- 
mediate ground. He may leave to the court or other 
authorized tribunal to decide whether the public has the 
facilities available at present for caring for a particular 
weak-minded person, but he must decide whether expert 
scientific opinion at the present time will justify diagnos- 
ing this degree of deficiency as suitable for the special 
care provided for the feeble-minded. Whether it is ad- 
visable to care for the particular deficient at home, in a 
special local school, or in a state institution would be left 
to the legal authority to decide. Under present con- 
ditions, the diagnostician may possibly indicate whether 
the individual is deficient enough to justify social isola- 
tion, or merely to justify sending to a local elementary 
day school for deficients. 

D. Percentages Suggested to Harmonize 
the Estimates 

It is from the point of view of the diagnostician that we 
shall attempt to focus this question of the percentage of 
feeble-minded. We shall tentatively suggest limits as 



PERCENTAGE INTELLECTUALLY DEFICIENT 53 

to the degrees of intellectual deficiency which we might 
be justified in regarding, under the present conditions of 
scientific knowledge as being low enough in intellectual 
capacity to justify particular forms of social care. Such 
estimates will be of value if they help to harmonize the 
conflicting opinions by bringing them into relation with 
the above analysis. We shall, therefore, compare the 
suggested percentages with a number of authoritative 
statements of the frequency of feeble-mindedness. By 
considering the differences in the nature of the estimations 
we may approach nearer to an understanding of the problem. 
Since the percentages to be suggested are chosen from 
the point of view of diagnosis, they do not represent the 
number for which every community should immediately 
make financial provision. The expense is a local or a 
state question. It is so much affected by state conditions 
and by public policy that it probably must be determined 
in any state by a special commission. On the other hand, 
the laws already provide for caring for the feeble-minded 
in institutions or colonies and in special schools or classes, 
so that the estimates may help to guide diagnosticians 
who are called upon to decide whether a particular person 
might be rightfully regarded as deficient enough intellect- 
ually to justify committing him for permanent care to a 
state institution. In the present practise it is fairly clear 
that this distinction is made in the minds of different 
diagnosticians. It may ultimately be desirable that this 
differentiation between the types of social care be intro- 
duced into the law. Until then it will remain the duty 
of the court to determine what degree of social unfitness 
is intended by a particular law. The social concept of 
feeble-mindedness is just now undergoing a rapid evolu- 
tion so that it would be impossible to predict how it may 
legally crystallize a generation hence. 



54 DEFICIENCY AND DELINQUENCY 

To begin with the lowest group of the feeble-minded, we 
should consider those whom the state might be clearly 
justified in isolating indefinitely on the basis of their 
tested lack of intellectual capacity, the social isolation 
group. For purposes of comparison let us place this de- 
gree of intellectual ability as that possessed by the lowest 
0.5% at fifteen years of age. Above these let us estimate 
a group of uncertain cases so far as isolation is concerned, 
but cases which the diagnostician would be justified in 
regarding as intellectually deficient enough to justify send- 
ing to special local schools for training the feeble-minded. 
After special training the majority of these cases might be 
expected to require social assistance indefinitely. They 
would form the social assistance group. Isolation would 
be justified for none of them on the basis of their test 
records alone. Those in this group who were persistent 
delinquents would, by that additional fact, fall into the 
lowest group so far as social care is concerned. Let us 
estimate this social assistance group tentatively as the 
next 1.0% at fifteen years of age. 

These estimates have been made as at fifteen years 
of age since the effect of the excessive mortality especially 
among the isolation group is uncertain and may need to 
be allowed for in a discussion of the percentage deficient 
at different ages. If the mortality were as great as has 
been described among institutional cases in the previous 
chapter, a rough estimate of the percentage intellectually 
deficient in the general population places it at less than 
0.5%. This estimate may be made by using the estima- 
ted deficiency at the median age of those under 15 years 
of age and at the median age of those 15 years of age and 
over. According to the age distribution of the 1910 
census, there were 32% under 15 years with a median 
age of 6 years. At age six 0.67% would be presumed as 



PERCENTAGE INTELLECTUALLY DEFICIENT 55 

low as 0.50% at 15 years. The older group (68% of the 
population) has a median age of 32 with a corresponding 
percentage in the isolation group at that age of 0.30%, 
after allowing for differences in mortality on the plan in- 
dicated in Table II. This rough estimate for the lowest 
group indicates that 0.42% of the general population 
would be of as low a degree of intellectual capacity as the 
lowest 0.5% at 15 years. Our plan presumes, therefore, 
that between 0.4% and 0.5% of the population are unable 
to pass their entire lives outside of institutions under or- 
inary conditions; i. e., make an honest living and live 
within the law even with social assistance and supervision. 

The corresponding estimate for those requiring only 
social assistance would be between 0.8% and 1.0% of 
the general population above the lowest group. This 
might vary from approximately 1.34% at 6 years to 0.59% 
at 32, the median age for those over 14 years. Since the 
mortality is probably less among deficients not in insti- 
tutions, as they average higher in ability, the changes in 
the percentages are probably extreme estimates. We 
should keep in mind, however, the possibility that with 
the excessive death rate the lowest 1.0% at 15 may mean 
an ability corresponding to the lowest 1.34% at 6 years 
and the lowest 0.60% at 32 years. 

The next higher group in intellectual ability is so high 
as not to require social assistance outside of school. 
When we ask how large a per cent, we should be justified 
in placing in this group and separating merely for special 
instruction in school, we reach a condition which is at 
present so ill-defined even in the minds of educators that 
it seems best to fall back on the general advice that our 
school systems should provide just as nearly individual 
instruction as the public purse and managing genius can 
devise. Mannheim, Germany, for example, takes care of 



56 DEFICIENCY AND DELINQUENCY 

18 per cent, outside of its regular school classes. The 
ideal is individual instruction for all. School authorities 
would be justified in providing special instruction for 
every degree of mental ability, if the cost would not re- 
strict other more important social undertakings. This 
less degree of retardation in the group needing only school 
assistance should not, however, be classed as feeble-mind- 
ed. We shall see later the percentages for which some 
authorities have considered it already advisable to pro- 
vide special school instruction. We need not attempt to 
estimate the size of this group, as it is beyond the limit of 
feeble-mindedness. 

The purely conative cases are not taken care of in the 
above estimates, which are intended for tested deficients. 
If the conative cases unaccompanied by intellectual de- 
ficiency should be regarded as frequent enough to replace 
those in the social assistance group who ultimately care 
for themselves, plus those subtracted by the excessive 
death rate, we would have a total of 1.5% of the general 
population feeble-minded enough to warrant social care 
of some sort. About 0.5% might justly be isolated. 
The reasonableness of this program can be judged by 
comparison with authoritative estimates now to be re- 
viewed. The problem here is whether this is an unreason- 
able program for the diagnostician to assume as scienti- 
fically justified, remembering that these estimates are for 
tested deficients at 15 years of age and do not include 
purely conative cases which might occur above these in- 
tellectual borderlines. 

E. Comparison with Important Estimates 

The Social Isolation Group. We are now ready to con- 
sider some of the important estimates which throw light 
upon the reasonableness of the percentages we have nam- 



PERCENTAGE INTELLECTUALLY DEFICIENT 57 

ed. First, what percentage would we be justified in 
socially isolating? In the United States Census Report 
on the Insane and Feeble-Minded in Institutions in 1910, 
we find that the number then actually in institutions for 
feeble-minded was only about 0.02% of the population. 
At the most frequent ages this rises to about 0.05%. It 
is evident that the number actually isolated is of little 
significance except as a check on the estimates. The 
report, however, refers to the special estimate made by 
the public authorities in Massachusetts which also in- 
cluded feeble-minded in state hospitals for the insane, 
other asylumns, those reported by the overseers of the 
poor and those enumerated in the general population. 
The U. S. report says: 'The census was not regarded as 
being complete, but it is of interest to note that if the 
number of feeble-minded in proportion to the total pop- 
ulation was the same for the entire United States as it was 
in Massachusetts according to this census, the total num- 
ber of feeble-minded would be over 200,000. Probably 
this may be regarded as a conservative estimate of the 
number of feeble-minded in the United States and would 
indicate that not over one-tenth of the feeble-minded are 
being cared for in special institutions" (205, p. 183). 
This estimate, which thus amounts to about 0.2%, may 
probably be considered as a reasonable program of ex- 
pansion from the institutional viewpoint. The diagnos- 
tician who is considering the individual and not the mass 
must supplement it by considering who should be isolated 
if facilities were available. If the census bureau can 
contemplate institutional care for ten times those at 
present thus provided for, it gives us some indication of a 
reasonable limit as to the increase in institutional care 
that can be assumed to be reasonably contemplated at 
present. 



58 DEFICIENCY AND DELINQUENCY 

Dr. W. D. Cornell, director of medical inspection of 
the Philadelphia public schools, after the personal ex- 
amination of those cases which in the opinion of the teach- 
ers should be sent to institutions, places the ' 'institution 
cases' ' at a minimum of 15 per 10,000 school children. 
He adds: 'The number of evidently feeble-minded above 
6 years of age may be said to be 1 to every 500 of the 
population. These figures are conservative and have 
been accepted by experts for years." This then is the 
minimum estimate and quite clearly refers to institutional 
cases. 

A committee of the Public School Alliance of New 
Orleans, of which Prof. David Spence Hill was chairman, 
reported in 1913 a careful census of the public school chil- 
dren in that city the previous year made by the teachers 
in co-operation with the Newcomb Laboratory of Psy- 
chology and Education. Each teacher was asked to state 
her opinion as to how many in her room were "feeble- 
minded or insane children who should be under institu- 
tional or home care, rather than in the public schools/' 
Also the number of backward children not in the above 
class "who urgently need special educational methods in 
special classes within the special schools." About a 
fifth of the total of the 38,000 school children in the city 
are colored. The grand total showed 0.28% in the first 
class mentioned above, and 7.7% in the second. Speaking 
of those "thought by teachers to be feeble-minded" and 
needing institutional care the report says: 

"The figure 0.28 of 1% coincides exactly with the esti- 
mate of the Philadelphia Teachers' Association made in 
1909 in a census of 150,000 school children. Secondly, 
while the teacher's estimates are open to revision, never- 
theless her judgment, as inevitably evidenced in her 
attitude toward the child, is the practically effective judg- 



PERCENTAGE INTELLECTUALLY DEFICIENT 59 

went" (157, p. 6). It is a well-known fact that teachers 
tend to underestimate the frequency of mental deficiency, 
so that it would certainly be a matter of regret if this were 
to continue to be the "practically effective judgment.' ' 

Another census of the institutional type of feeble-mind- 
ed made by the Director of Public Health Charities in 
Philadelphia and reported in 1910 enumerated 0.2% of 
the population as in this group. It included cases in the 
institutions for feeble-minded, the insane hospitals, alms- 
houses, hospital, reformatories, orphanages and known to 
charity workers {168, p. 13). 

One of the most careful surveys of individuals who, 
because of mental abnormalities, _ show such social mal- 
adjustment as to become the concern of public authorities 
was made under the auspices of the National Committee 
for Mental Hygiene in 1916.* It selected Nassau Coun- 
ty as representative of New York state. Part of the 
survey consists of an intensive house to house canvass of 
four districts of about a thousand population each. The 
result disclosed that 0.54% of the population of this coun- 
ty were socially maladjusted because of "arrests in de- 
velopment" and 0.06% more, because of epilepsy. This 
was in a population of 115,827. 

The Children's Bureau in the U. S. Department of 
Labor in 1915 made a census of the number of "mental 
defectives" in the District of Columbia. The census in- 
cluded only those whom we have termed feeble-minded. 
The report states that 798 individuals, 0.24% of the pop- 
ulation, were found to be "in need of institutional treat- 
ment; and the number reported, allowing for the margin 
of error in omission and inclusion, is probably a fair 

* Aaron J. RosanofL Survey of Mental Disorders in Nassau County, 
New York. Publication No. 9, National Committee for Mental Hy- 
giene, 1917. 



60 DEFICIENCY AND DELINQUENCY 

representation of the number in the District who should 
have custodial care" (88, p. 13). Over a quarter of the 
population of the District is colored. The census was 
taken in connection with plans for immediate care. The 
same Bureau also made in 1915 and 1916 a Social Study of 
Mental Defectives in New Castle County, Delaware.* This 
county had a population of 131,670 and the survey dis- 
closed 212 "positive cases of mental defect" and 361 
"questionable cases," a total of 0.44% of the general 
population in this county. Among the positive cases, 
82.5% were in need of public supervision or institutional 
care. Among the questionable cases, information was 
obtained about only 175, and 165 of these were either in 
institutions, delinquent or uncontrollable, or living in 
homes where proper care and safeguarding were impos- 
sible. 

Two other important attempts to enumerate carefully 
all the feeble-minded in definite areas in the United States 
have been made in recent years. Lapeer County, Mich., 
was chosen for such a study, as it was of average size and 
contained no large city. The census as reported in 1914, 
showed 36 feeble-minded from that county in the state 
institution and 116 others living in the county, a total of 
1 from every 171 inhabitants (145). A special children's 
commission was appointed by the state of New Hampshire 
to investigate the welfare of dependent, defective and de- 
linquent children. Its report in 1914 contained a section 
by its chairman, Mrs. Lilian C. Streeter, on feeble-mind- 
edness (40). This comes the nearest to a complete enu- 
meration for an entire state which has ever been attempted. 
The commission tested with the Binet scale the inmates 



*Emma O. Lundberg. A Social Study of Mental Defectives in New 
Castle County Delaware. U. S. Dept. of Labor, Children's Bureau. 
Publication No. 24, 1917, pp. 38. 



PERCENTAGE INTELLECTUALLY DEFICIENT 61 

of the State Hospital for the Insane, the County Farms, 
the State Industrial School and the Orphanages within 
the state. The borderline which it used for the scale 
was high. It counted all those testing three or more years 
retarded and under XII as feeble-minded. Taking its 
figures as they stand we find that they listed 947 as feeble- 
minded in institutions and 2,019 outside, a total of 0.69% 
of the inhabitants of the state. Outside the institutions 
the commission sent a questionnaire to all school superin- 
tendents and to chairmen of school boards, physicians, 
overseers of the poor, county commissioners, probation 
and truant officers, district nurses and charity workers 
throughout the state, by which means they listed 792 
additional cases. This questionnaire gave the following 
description of the type of case it was trying to list as feeble- 
minded. 

' The high grade imbecile, frequently known as the 
moron, is one who can do fairly complicated work with- 
out supervision, but who cannot plan, who lacks ordinary 
prudence, who cannot resist the temptations that are 
common to humanity. The high grade imbecile is most 
dangerous because, except to the expert, he is apparently 
not feeble-minded and is, therefore, usually treated as 
normal, and permitted to multiply his kind, and to cor- 
rupt the community/ ' 

This description would tend to include cases above our 
isolation group. Besides the questionnaire the commis- 
sion made an intensive study of 52 towns in which it 
says practically complete census returns were obtained 
by consulting doctors, school and town officials. With 
these supplementary cases it secured a list of 2,019 cases 
outside of institutions, making a total of 2,966 recorded 
cases within the state or 0.69% of the population. When 
it estimated the proportion for the entire state on the 
basis of the rate of canvass returns to questionnaire re- 



62 DEFICIENCY AND DELINQUENCY 

turns, this proportion rose to 0.95%. The commission 
does not advocate compulsory isolation for all of these 
people although it recommends custodial care for the 
feeble-minded women and girls of child-bearing age, ap- 
parently of the degree of deficiency represented by its 
criteria. This enumeration of 0.69% of the people of a 
state as feeble-minded is the most liberal general census of 
the feeble-minded in any large area. It clearly shows the 
trend of diagnosis since the British Census. 

The Extension Department of the Training School at 
Vineland, N. J., states regarding estimates of the number 
of feeble-minded in the general population: "Conserva- 
tive estimates give one in three hundred as the probable 
present number." Under the discussion of estimates of 
the general population I have already cited Goddard's 
estimate which was approximately 0.3 to 0.4% and the 
enumeration of 0.4% by the British Royal Commission 
in 16 districts with over two million population. While 
all of these estimators are speaking broadly of the feeble- 
minded, in the general population, we shall not be far 
wrong in supposing that they are considering mainly those 
deficients for whom the state might well expect to pro- 
vide care for life, isolating all those who cannot be eugen- 
ically guarded at home. We shall later quote the estimate 
of Van Sickle, Witmer and Ayres of 0.5% of the school 
population as "institution cases/ ' 

Our estimate of 0.5% in the group justifying isolation 
on the ground of intellectual deficiency seems to be con- 
servative and to harmonize fairly this type of estimate. 

The Social Assistance Group. Passing now to the next 
higher group of deficients, those needing special training 
in order to get along with social assistance, the estimates 
have been based almost entirely upon the study of school 



PERCENTAGE INTELLECTUALLY DEFICIENT 63 

children. Francis Warner was the moving spirit in the 
early investigations in Great Britain, which were made 
without tests from 1888 to 1894. The census which he 
directed included about 100,000 school children who 
passed in review before medical examiners. As cited by 
Tredgold (204) the estimate growing out of this work 
was that 1.26% of the school population should have 
instruction in special classes. Of these 0.28% required 
special instruction because of physical defects only (204) . 

About the same time Will S. Monroe (155) on the basis 
of a questionnaire sent to California teachers, who reported 
on 10,842 school children, found that they estimated 
1,054 of these as mentally dull in school, 268 feebly gifted 
mentally, and 6 imbeciles and idiots. He summarized 
his conclusion as follows: "A long experience teaches that 
every school of fifty pupils has at least one child that can 
be better and more economically trained in the special 
institutions than in the public. schools/ ' In his estimate 
of 2% he was probably thinking of care in special local 
schools and not permanent isolation. 

A government inquiry of school teachers in Switzer- 
land, who had charge of 490,252 school children, reported 
that 1.2% were so feeble mentally as to need training in 
special classes. Only about a tenth of this number were 
then being instructed in separate classes (181, p. 17). 

Great Britain first gave legal recognition to the class 
of feeble-minded above the imbeciles in its Education Act 
of 1898, following a report of a departmental committee 
of its National Board of Education growing out of the 
inquiries of Francis Warner. This committee estimated 
the proportion of this class as approximately 1% of the 
elementary school population (181). In discussing the 
comparative estimates on the general and school popula- 
tions I have already referred to the estimate of Tredgold 



64 DEFICIENCY AND DELINQUENCY 

based upon an elaborate analysis of the most extensive 
data ever collected, — that gathered by the British Royal 
Commission on the Care and Control of the Feeble-Mind- 
ed. While the Commission's investigators enumerated 
0.79% among the school as mentally defective, Tredgold's 
estimate based on his analysis of their report was that 
0.83% of the school population in England and Wales 
were above the grade of imbecile but still feeble-minded 
(204, p. 157). The variability of the estimates collected 
by the Royal Commission from various cities probably 
indicates the subjective character of the standards of de- 
ficiency. They varied from an estimate of 0.24% of the 
elementary school population in Durham to 1.85% in 
Dublin (204, p. 159). The Commission says regarding 
estimates as to communities other than those reported 
by their medical investigator, for Newcastle the "number 
of feeble-minded children of school age" (morons) was 
0.25%, for Leeds the estimate was 0.80%, for London 
0.50% or 0.60%, for Bradford 0.50%, for Dublin about 
1% and for Birmingham about 1% of the school popula- 
tion. Dr. Francis Warner's general estimate was 0.8%. 
We have thus variations in estimates from 0.25%, 0.5%, 
0.80% to 1% and some 2%" (167, p. 90). For the rural 
area& the estimates were generally less. 

A careful estimate has been made with a different meth- 
od by Karl Pearson on the basis of a classification by 
teachers of school children in Great Britain into nine 
different classes each especially defined and extending 
from the imbecile to the genius. This distribution of the 
children was then fitted to the normal probability curve. 
On this basis Pearson estimated that 1.8% would fall in 
the "very dull group," defined as having "a mind capable 
of holding only the simplest facts, and incapable of grasp- 
ing or reasoning about the relationship between facts; 



PERCENTAGE INTELLECTUALLY DEFICIENT 65 

the very dull group covers but extends somewhat further 
up than the mentally defective/ ' Lower down would be 
0.1% in the imbecile group. He says further regarding 
this estimate: "It is deduced from three series covering 
between 4000 and 5000 cases, and the three separate re- 
sults are in several accord. It will, I think, be possibly 
useful for other inquirers, and it endeavors to give quanti- 
tative expression to our verbal definitions of the intellectual 
categories" (166)* 

In 1914 Pearson cites estimates of mentally defective 
children in several cities by teachers and medical officers 
based upon the recommendation of elementary school 
children for special schools and classes. These were, for 
London: boys, 1.59%; girls, 1.09%. For Liverpool: boys, 
0.827%); girls, 0.618%. The corresponding figure for 
both sexes in Stockholm is 1.23%. He concludes that 
"something between 1% and 2% is true for England. 
Dr. James Kerr, Medical Research Officer, thinks that 
the final estimate will be nearer the latter value." 

After giving a table of the percentages at each age in 
the elementary schools of Stockholm, Pearson says: "Jud- 
ged from this table it would seem that the most reasonable 
estimate of the prevalence of mental defect is to be formed 
when all the mental defectives have been definitely selec- 
ted and the normal children have not yet begun to leave 
school, i. e., at the ages 11 and 12. For Stockholm this 
leads up to a mentally defective percentage of about 1.5" 
(167, p. 6-8). In another place he says that the members 
of special classes are selected practically for the same 
reason, i. e., because they are school inefficients, the bulk 



*This statement in 1906 seems to be the earliest attempt at a quanti- 
tative definition of deficiency. As I discovered it after the present 
monograph was practically completed, it furnishes evidence of the nat- 
ural tendency of attempts at more exact definition to take the percentage 
form. 



66 DEFICIENCY AND DELINQUENCY 

of whom will, no doubt, unless provided for become ' 'so- 
cial inefficients" {164, p. 48). Since some were not selected 
because of intellectual deficiency, our social assistance 
group should be somewhat smaller. 

In 1909-10 the actual number in the schools for mental 
defectives maintained by the London County Council 
was 0.9% of the enrollment of the London elementary 
Schools (143). The 1912 report of the London County 
Council shows 7357 children enrolled in its local schools 
for mental defectives, which is 1.1% of the average 
attendance from 1912-1913 in the elementary county 
council schools and voluntary schools of London {144, p. 
44). 

Following a discussion in the Australian Medical Con- 
gress of 1911 the Minister of Public Instruction called for 
returns as to the number of feeble-minded in the Australian 
public elementary schools between $y 2 and 14 years of 
age inclusive. The questionnaire used the definitions 
of the British Royal Commission as a description of the 
various degrees of retardation and brought returns from 
2,241 of the state schools, all except 57. For their average 
attendance of 175,000 children, these teachers classified 
1.9% as backward from accidental causes, 2% mentally 
dull, 0.42% feeble-minded imbeciles or idiots, and 0.6% 
epileptics. To this w r ould be added 0.19% for children in 
the idiot asylums. The report states that "the teachers 
estimates will thus be realized to be an absolute minimum, 
dealing only with the intermediate grades, and not in- 
cluding the gross cases (idiots, etc.) on the one hand and 
the less marked high grades of feeble-minded on the other' ' 
(70). 

The census made by the Bureau of Health of Phila- 
delphia through the principals of schools in 1909 covered 
157,752 elementary school children of whom 1.9% above 



, PERCENTAGE INTELLECTUALLY DEFICIENT 67 

the 0.28% who could "properly be in custodial institutions 
'were classed' as backward children who require special in- 
struction by special methods in small special classes' ' (168). 

A survey of the school population in the Locust Point 
District of Baltimore was made by Dr. C. Macfie Camp- 
bell.* The district surveyed was, however, not consid- 
ered typical of Baltimore, but was a sample of an in- 
dustrial district in which the majority of families are 
"close to the poverty line, and too often below it." Out 
of a school population of 1,281 children, 166 (13%) were 
"found to have special requirements on account of their 
mental constitution/ ' Among these, 22 (1.7%) "showed 
a pronounced mental defect, which eliminated any pros- 
pects of their becoming self-supporting. ,, 

The city of Mannheim (147), which perhaps cares for its 
exceptional children better than any other in the world, 
was in 1911-1912 caring for 0.7% of the children in its 
Volkschule in Hilfsklassen which do not take them beyond 
the fourth grade. There were 12% more who were back- 
ward in school and being taught in Forderklassen where 
they may reach the sixth grade. Including the excep- 
tionally bright who were also in special classes, 18% all 
together of its school children were not in the regular 
Hauptklassen of the eight grades. To these would be 
added those sent to special institutions. When we esti- 
mate, therefore, that we are justified at present in send- 
ing 1% of the children in school to special classes because 
their intellectual deficiency is such that the bulk of them 
cannot get along without social assistance, we are 
naming about the proportion already thus cared for in 
several foreign cities. 

*C. Macfie Campbell. The Sub-Normal Child— A Study of the 
Children in a Baltimore School District. Mental Hygiene, 1917, I, 
96-147. 



68 DEFICIENCY AND DELINQUENCY 

Among the authoritative estimates of the number of 
feeble-minded, which have been made by estimators who 
had in mind the evidence from mental tests, is that 
made by James H. Van Sickle, Lightner Witmer, and 
Leonard P. Ayres in a bulletin published by the United 
States Bureau of Education in 1911 (209). They state 
that, "if all children of the public schools could be ranked, 
it is probable that a rough classification would group 
them about as follows — Talented, 4%; Bright, Normal, 
Slow, 92%; Feeble-Minded, 4%. The 4% may for 
administrative purposes be divided into two groups. 
The lower one includes about one-half of one per cent, of 

the entire school membership They are 

genuinely mentally deficient, and cannot properly be 
treated in the public schools. They are institution cases, 
and should be removed to institutions. Ranking just 
above these are the remaining three and one-half per cent, 
who are feeble-minded but who could be given a certain 
amount of training in special classes in the public schools/ ' 
The estimate of institutional cases practically coincides 
with that adopted above in this paper. The extension of 
the term feeble-minded to include the lowest 4% seems 
to be extreme. The authors do not suggest what portion 
of these they think might require social assistance in- 
definitely, but are interested primarily in provision for 
special classes in the public schools. If the term feeble- 
minded were to mean only unfit for regular school classes 
and not socially unfit, I have already suggested that the 
limit for special instruction might be increased indefinite- 
ly. In Mannheim 18% are not cared for in the regular 
classes. 

The only estimate of feeble-minded which I have found 
that is so large as this 4% is that of Binet. It is also in- 
tended to cover all cases that should be sent to special 



PERCENTAGE INTELLECTUALLY DEFICIENT 69 

classes regardless of subsequent social survival. His 
statement as to those who are so abnormal or defective 
as to be suitable for neither the ordinary school nor the 
asylum is as follows: 

'As to France, precise information has not been avail- 
able until the last year, when two inquiries were held — 
one at the instance of the Ministerial Commission, the 
other organized by the Minister of the Interior. Ac- 
cording to the former inquiry we find that the proportion 
of defectives amounts to scarcely 1% for the boys, and 
0.9% for the girls. These percentages are evidently far 
too small, and we ourselves have discovered, by a small 
private inquiry, that many schools returned "none" in 
the questionnaires distributed, although the headmasters 
have admitted to us that they possessed several genuine 
defectives. In Paris, M. Vaney, a headmaster, made 
some investigations by the arithmetic test, which we 
shall explain presently, and reached the conclusion that 
2% of the school population of two districts were back- 
ward. If we were to include the ill-balanced, whose num- 
ber is probably equal to that of the backward, the pro- 
portion would be about 4%. Lastly and quite recently 
a special and most careful inquiry was made at Bordeaux, 
under the direction of M. Thamin, by alienists and the 
school medical inspectors, and it was found that the per- 
centage of abnormality amongst the boys was 5.17. Prob- 
ably the true percentage is somewhere in the neighbor- 
hood of 5. All these inquiries are comparable because 
they deal with the school population" (77, p. 8). 

In this estimate of 5%, Binet was considering those to 
be sent to special classes regardless of whether or not they 
would require indefinite social assistance after their school- 
ing. It is therefore not directly comparable with our 
estimate of 1.5% presumably or doubtfully intellectually 
deficient. 

The estimate of Dr. Henry H. Goddard, who has done 
the most to introduce the Binet Measuring Scale in this 



70 DEFICIENCY AND DELINQUENCY 

country, is stated as follows: "It is a conservative state- 
ment to declare that 2% of public school children are 
distinctly feeble-minded, the larger part of them belong- 
ing to this high-grade group which we call morons' ' (118). 
In another (114) place he says: "The most extensive study 
ever made of the children of an entire school system of two 
thousand has shown that 2% of such children are so mentally 
defective as to preclude any possibility of their ever being 
made normal and able to take care of themselves as adults."* 
The study to which he refers gives individual results with 
the Binet 1908 tests made on 1547 school children in the 
first six grades (114, p. 43). Since the sixth grade does 
not include the better children who are twelve years or 
over in age this group is clearly selected in such a way that 
it would show an excessive percentage of mentally re- 
tarded children. We find in the investigation referred to 
that he says: "Then we come to those that are four years 
or more behind their age, and here again experience is 
conclusive that children who are four years behind are so 
far back that they can never catch up, or in other words, 
they are where they are because there is a serious difficulty 
which can never be overcome — they are feeble-minded. 
They constitute 3% of the children in these grades/ ' 

Since we have a random selection of school children in 
his table for only those children who are 6 to 11 years of 
age inclusive, I find that only 1% at these ages are re- 
tarded four years intellectually. On his own basis, there- 
fore, 3% is evidently too large an estimate. Later he 
seems to have reduced his estimate to 2% of the school 
population. Of those who test in the lowest 1.5% in- 
cluding our doubtful group, I believe that there is no clear 
evidence that more than 1% will require even social 
assistance as adults. 



*Italics mine. 



PERCENTAGE INTELLECTUALLY DEFICIENT 71 

Many more estimates of the number of feeble-minded 
among school children might be cited, but they would add 
little to these authoritative samples. At the present time 
an estimate by health officers or teachers who are not 
familiar with the results of mental testing has little 
significance, as the whole complexion of the problem has 
been changed since the work of Binet and Simon. * We 
may, however, cite three estimates based upon familiarity 
with test results, which fairly cover the range of estimates 
among school children.- In connection with the Spring- 
field, Illinois, survey conducted by the National Com- 
mittee for Mental Hygiene under the direction of the Rus- 
sel Sage Foundation, we find that three typical schools 
with a total of 924 pupils were studied. The report states 
that "the mentally defective children" constituted 3.8% 
of. the number in attendance in March. The number of 
children in the schools examined, for whom instruction 
in special classes would be desirable, is about 7% of the 
entire enrollment of these schools" (203, p. 10). 

In connection with the Stanford Version of the Binet 
Scale, Dr. Lewis M. Terman says: "Whenever intelligence 
tests have been made in any considerable number in the 
schools, they have shown that not far from 2% of the 
children enrolled have a grade of intelligence which, how- 
ever long they live, will never develop beyond the level 
which is normal to the average child of 11 or 12 years. 
. . . The more we learn about such children, the clear- 
er it becomes that they must be looked upon as real de- 
fectives (57, p. 10). Again in placing the borderline for 
feeble-mindedness" with the Intelligence Quotient used, 



*The report of the Massachusetts Commission on Mental Diseases 
(Vol. I, p. 198) shows that social agencies systematically using mental 
tests reported 19.2% as mental cases, while those using examinations 
only for obvious cases reported 1.3%. 



72 DEFICIENCY AND DELINQUENCY 

he suggests that "definite feeble-mindedness" lies below 
an I. Q. of .70 which with 1000 quotients was found 
to exclude about the lowest 1%. Above this is a group 
with I. Q.'s 70-80 which he describes as "borderline 
deficiency, sometimes classifiable as dullness, often as feeble- 
mindedness/' This group would include, as judged by 
the results of these tests, over 4^ more. 

Dr. Wallin, who has had wide experience in testing both 
school children and defectives, states: "I will venture the 
assertion, after years of teaching in the public schools and 
clinically examining public school cases, that the oft- 
repeated statement that 2^ of the general school popula- 
tion is defective (if by this is meant feeble-minded), ex- 
aggerates the real situation. The actual number is prob- 
ably about 1%" {211, p. 149). 

After reading a paper on "A Percentage Definition of 
Intellectual Deficiency' ' before the American Psycholog- 
ical Association in 1915 {151), I was pleased to 
discover that Prof. Rudolf Pintner and Donald G. Pater- 
son were also about to propose a percentage definition of 
feeble-mindedness for those who are dealing with mental 
tests {44). While their idea seems to be fundamentally 
similar, their paper shows that their conception is to be 
sharply distinguished in several particulars from that 
which I am advocating. They would limit the use of 
the term "feeble-mindedness" to individuals who test 
in a rather arbitrarily chosen lowest percentage of the 
population. As opposed to this I suggest continuing 
the present social definition of feeble-mindedness and sup- 
plementing it, for the purpose of aiding in the diagnosis, 
by indicating the social significance of those testing in 
certain low r est percentages. Such tested deficients I 
designate as "intellectually deficient." It is important 
to consider their statement and to note what percentage 



PERCENTAGE INTELLECTUALLY DEFICIENT 73 

they have chosen to regard as feeble-minded. They say: 

"It is in order to avoid this vagueness and uncertainty attaching to 
the term that we suggest a definite psychological concept. The lowest 
three per cent of the community at large, that is, the lowest as deter- 
mined by definitely standardized mental tests, are to be called feeble- 
minded. Such a definition will be unambiguous and the dividing line 
between this and other groups will become clearer and clearer as we in- 
crease the accuracy of our measuring scales and the adequacy of our 
standardizations. Furthermore, if evolution is raising the degree of 
intelligence the three per cent at the lower end will still remain, for, 
whatever the degree of their intelligence may be, they will still be feeble- 
minded as compared with the normal. 

"Such a definition will in addition restrict the term to such as are 
lacking in intelligence and will differentiate them from the moral de- 
fectives and the psychopathic personalities, which are at present often 
confused with the group that we propose to call feeble-minded. An 
individual may be at the same time a moral defective and feeble-mind- 
ed, but there is reason to believe that moral deficiency may exist 
without such intellectual defect as to warrant a diagnosis of feeble- 
mindedness. The same may be said of the psychopathic personality. 

"The further question, whether all those coming within the proposed 
definition of feeble-mindedness are to be confined in institutions, is 
purely social and will be determined by the social needs of each com- 
munity and does not concern us here. It is obvious that many more in 
addition to the feeble-minded as defined by us will require the restraint 
of an institution, even though no real mental defect exists. 

"It is immaterial for the purposes of this hypothesis whether three or a 
smaller or larger percentage be designated as feeble-minded. The im- 
portant point is the agreement upon some fixed percentage, and we 
have chosen three per cent as covering presumably all the cases of 
marked mental deficiency. A brief glance at the chief estimates of 
the number of feeble-minded in civilized communities would indicate 
that our percentage is somewhat higher than the conservative writers 
give, but we shall show later on that it is much lower than the results 
obtained from groups of children tested by intelligence scales" {44, p. 36). 

With those who understand that deficiency is mainly 
a question of degree, it would seem that there might be 
some agreement as to the plan for defining tested deficiency. 
In order to make this plan more useful to those dealing 



74 DEFICIENCY AND DELINQUENCY 

with the social care of the feeble-minded, it would be 
necessary to supplement the bare percentage definition 
by relating it to expectations of social failure somewhat 
after the manner I have attempted. In particular it will 
gain its main value for diagnostic purposes, it seems to me, 
if the percentage is so chosen that it may receive the sup- 
port of conservative scientific opinion. To be most useful 
it seems evident, also, that the percentages must be chosen 
with regard to the sort of social care which it is antici- 
pated would be justified for the particular degrees of de- 
ficiency. 

Let us recall the percentages suggested to harmonize 
the estimates: the lowest 0.5% to be regarded as pre- 
sumably deficient enough to justify isolation and the next 
1% as doubtful, but low enough to warrant special train- 
ing and probably requiring indefinite social assistance. 
If these percentages for tested intellectual deficiency 
have been shown to be fairly conservative estimates in 
the light of the authoritative judgments with which they 
have here been compared, the laboriousness of this com- 
parison has been worth while. Further light upon the 
social assistance group may be thrown by the study of 
the success of those children who have already had the 
advantage of training in local classes for the deficient. 

F. The Ability of the Mentally Retarded, 
Especially Those Receiving Special Training. 

That we are not justified in isolating all whom we class 
as feeble-minded is best indicated by the evidence as to 
the number of these sent to special local classes for de- 
ficients who are able to float socially with the assistance 
of capable after-care committees. A fair picture of the 
present situation may be obtained by thinking of these 
pupils in the help-classes and schools as representing about 



PERCENTAGE INTELLECTUALLY DEFICIENT 75 

the next 1% above those who have been isolated in in- 
stitutions. With this picture in mind let us see what has 
been the outcome of their special instruction and social 
assistance thereafter. 

In his book on Les Enfants Anormaux, Binet collected 
the evidence available at that time (77, p. 140). He 
says: 

"Mme. Fuster, after a stay in Germany, where she visited some 
Hilfschiden and Hiljsklassen (literally, 'help-schools' and 'help-classes') 
made a communication to the Societe de V Enfant, from which it appears 
that in the case of 90 classes for defectives in Berlin, 70% to 75% of 
the defective pupils who were there became able to carry on a trade; 
20% to 30% died in the course of study, or returned to their homes, or 
were sent to medical institutions for idiots. 

"According to a more recent inquiry, made under the auspices of M. 
de Gizycki at Berlin, and published in a book by Paul Dubois, 22% 
of the children were sent home or to asylums; 11% were apprenticed; 
62% worked at occupations which required no knowledge and yielded 
little pay (laborers, crossing-sweepers, ragmen). If we add together 
these two last groups, we reach a proportion of 73% of defectives who 
have been made, or who have become more or less useful. .... 

"Dr. Decroly has kindly arranged at our request a few figures re- 
lating to the occupational classification of the girls discharged from a 

special class in Brussels Finally, then, out of nineteen 

feeble-minded subjects, regarding whom particulars have been supplied, 
one-half, or 50%, have been apprenticed, or more than half, 75% if 
we count the defectives who 'work.' ... ... 

"Through the intervention of an inspector, M. Belot, we have in- 
quired of twenty heads of schools what has become of the defectives 
whom they notified to us two years ago. We have made these inquiries 

with regard to sixty-six children only If we subtract 

the two first groups, those about whom the particulars are wanting, 
and those who have not yet left school, there remain twenty-seven 
children, of whom seventeen have been apprenticed, or 76% . . . . 
Now this proportion is, by an unexpected agreement, identical with 
that obtained in the classes of Berlin and Brussels." 

A more recent report concerning the Hilfsschulen in 
Berlin by Rector Fuchs is in close agreement. It indi- 



76 DEFICIENCY AND DELINQUENCY 

cates that from 70% to 80% of the former pupils of these 
schools make a living after they leave school. 

To compare with these reports indicating that about 
three-fourths of those leaving the special schools of Paris, 
Berlin and Brussels by social assistance attain occupational 
classifications, we have less favorable reports from Great 
Britain. Shuttleworth and Potts (181, p. 23) say: 

"At the Conference of After-Care Committees held in Bristol on 
October 22, 1908, a paper read by Sir William Chance, Chairman of 
the National Association for the Feeble-Minded, dealing with the re- 
ports of the After-Care Committees of Birmingham, Bristol, Leicester, 
Liverpool, London, Northampton, Oldham and Plymouth. The com- 
bined statistics from the nine centers showed that 22% of those who 
had attended special schools for the mentally defective were in regular 

work, and 6.8% had irregular work To illustrate the 

necessity for continuous supervision and the futility of temporary care, 
we cannot do better than quote the records of the Birmingham After- 
Care Committee, as embodied in their report for 1908, after seven years 
work. It was found that, 'out of 308 feeble-minded persons who have 
left school and are still alive, only 19.8% are earning wages at all, 
and only 3.9% are earning as much as 10 s. per week* " (181). 

Tredgold summarizes other data on this question of in- 
dustrial success as follows: 

"We may next turn to the reports of * After-Care' Committees re- 
garding feeble-minded (moron) pupils of the special schools. In Lon- 
don the proportion of pupils known to be in 'good or promising' em- 
ployment was 37.5%. Two years previously it had been 45.7%, and 
Sir George Newman, the Chief Medical Officer to the Board of Educa- 
tion, attributes the falling off to two causes— firstly, insufficient after- 
care; and secondly , the two additional years. He remarks: The longer 
the test the more severe it is.' In Birmingham, the 'After-Care' Com- 
mittee compiled information regarding 932 cases which had passed 
through the schools during the previous ten years. Of these, excluding 
the normal and dead, 272, or 34%, were engaged in remunerative work. 
At Liverpool, of 712 children passing through the hands of the 'After- 
Care' Committee during a period of six years, 85, or 11.9%, were doing 
remunerative work. 

"Finally we may refer to some figures concerning 'After-Care' work 
compiled by Sir William Chance from the returns of the National As- 



PERCENTAGE INTELLECTUALLY DEFICIENT 77 

sociation for the Feeble-Minded. These were based upon an inquiry 
made of sixteen centers of the Association, and referred to a total of 
3,283 persons. Of this number, 798 were doing remunerative work, 
89 were 'doing work, but not reported ;' 202 were useful at home; and 
941 were returned as 'useless members of society/ If we exclude 340 
who were transferred to normal schools (not being feeble-minded), we 
have 27% engaged in remunerative work. 

"With regard to the term 'remunerative work/ however, it is to be 
remarked that the person employed is not being paid the standard 
wage. On the contrary, it is my experience that this is practically 
never the case, and this is corroborated by the observations of the 
secretary of the Birmingham center, who says: 'Although some of our 
cases have been at work for more than ten years, only 34 of the whole 
number (173) earn as much as 10s., 2 d., per week. Of these only 6 
earn as much as 15 s., and only 2 earn 20 s., which is the highest wages 

earned While it is not very difficult for some of our 

higher-grade cases to get work when they first leave school, it is almost 
impossible for them to retain their situations when they get older, and 
the difference between them and their fellows becomes accentuated. 
Uncontrolled and often quite improperly cared for, they rapidly de- 
teriorate, the good results obtained by the training and discipline of 
the special school being under these circumstances distinctly evanes- 
cent There are few workers over twenty years of 

age' " (204, p. 425, 435). 

The 1912 report of the London County Council (144) 
covers those who left its special schools for mentally de- 
fective children during the years 1908-1912 inclusive. 
These schools have accommodation for about 1% of the 
elementary school enrollment. Of 2010 children who 
left these schools during these five years, and who were 
still alive, 1357 were employed and 311 more employed 
when last heard from, a total of 79% employed 
at last accounts. Those out for five years show about the 
same proportion employed. This is a more favorable 
showing and fairly in line with the results of other Europ- 
ean help-schools. The average weekly wages of those 
employed ranged from 4 s. 6 d. for those just out to 10 s. 



78 DEFICIENCY AND DELINQUENCY 

10 d. for those leaving five years before. A considerable 
proportion who live at home thus have been meeting 
their necessary living expenses as the result of this special 
training and subsequent assistance. 

Dr. Walter E. Fernald reported to the British Royal 
Commission on the Care and Control of the Feeble- 
Minded concerning the inmates of the institutions for 
feeble-minded in the United States. These institutions 
receive a much lower grade of cases on the whole than 
the local help-schools abroad: (83, Vol. VIII, p. 159) 

"Some of the institutions where only the brightest class of imbeciles 
are received, and where the system of industrial training has been very 
carefully carried out, report that from 20% to 30% of the pupils are 
discharged as absolutely self -supporting. In other words at other in- 
stitutions, where the lower grade cases are received, the percentage 
of cases so discharged is considerably less. It is safe to say that not 
over 10% to 15% of our inmates can be made self-supporting, in the 
sense of going out into the community and securing and retaining a 

situation, and prudently spending their earnings 

But it is safe to say that over 50% of the adults of the higher grade 
who have been under training from childhood are capable, under in- 
telligent supervision, of doing a sufficient amount of work to pay for 
the actual cost of their support, whether in an institution or at home." 

The wages of the women at the Bedford Reformatory 
before entering prostitution as given by Davis (133, p. 210) 
have a direct bearing on the earning capacity of the higher 
grade feeble-minded. The Binet tests of Bedford wo- 
men by Weidensall indicate that about 38% of the suc- 
cessive cases admitted to Bedford test in the lowest 0.5% 
intellectually, and 75% in the lowest 1.5% intellectually. 
Davis' table shows that for 110 whom she classes as ment- 
ally low grade cases at the reformatory, the median wage 
of those in domestic service, as claimed by the women, 
was nearly $4.50 before entering prostitution. These 
feeble-minded women, if their statements of earnings can 



PERCENTAGE INTELLECTUALLY DEFICIENT 79 

be accepted, are therefore feeble-minded by reason of their 
low intelligence plus delinquency, and not by reason of 
inability to earn the necessities of life. The best of these 
mentally low grade cases earned as high as $5.00 in addition 
to board and lodging in domestic service and $25.00 out- 
side of domestic service. 

In this country we have fewer studies of the results of 
training the mentally retarded in special local classes 
and schools. Miss Farrell has made a preliminary report 
of 350 boys and girls out of the 600 children formerly in 
the ungraded classes in New York City during the pre- 
ceeding 8 years (102). Omitting seven whose status was 
unknown and 10 who had died, only 6% were known to 
have failed to survive socially with assistance. These 
were in penal or other institutions. On the other hand a 
strict analysis of her returns shows only 28% earning 
$5.00 a week or more and thus possibly surviving inde- 
pendently. Of the above group of 333, 86 were at home, 
192 employed, 31 unemployed and 3 married. 

In Detroit among 100 children over 16 years of age who 
had attended its special classes and been out of school not 
over 5 years, 27 had been arrested, but 39 of the boys had 
been at work and received an average wage of $7.00 per 
week, while 16 girls had averaged $3.75 in weekly wages, 
although few held their positions long (97). 

Bronner (6) compared a random group of thirty de- 
linquent women at the detention home maintained by the 
New York Probation Association with an intellectually 
similar group of 29 women all of whom had been earning 
their living in domestic service and none of whom had 
been "guilty of any known wrong doing." The delin- 
quents were 16 to 22 years of age while the servant group 
was somewhat older. Only two or three of the delinquent 
group were worse than the poorest of the servant group in 
any of the five intellectual tests, so that, if more than this 



80 DEFICIENCY AND DELINQUENCY 

number were intellectually deficient, they were no more 
deficient than those who had survived in society. No 
Binet scale records were published so that we have no 
means of determining how many of these delinquents 
might fall within either of our deficient groups. 

The principal deduction from this evidence on the 
earning capacity of those of low intellectual grade is a 
caution against demanding the social isolation of all the 
intellectually weak until we have more definite informa- 
tion as to what portion of them are able to live moral lives, 
as well as earn their living with social assistance, without 
being cared for entirely in isolation colonies. That a 
significant number of the lowest 1.0% intellectually next 
above the lowest 0.5% have led moral lives and have 
shown considerable earning capacity after attending 
special schools, when they are given proper after-care, 
has probably been demonstrated. They should, there- 
fore, be treated as an uncertain group whose feeble-mind- 
edness would never be decided purely on the ground of 
the intellectual tests. Most of them will, however, prob- 
ably be found mentally deficient enough to need at least 
social assistance and protection. 

In concluding this summary on the estimates of the fre- 
quency of feeble-mindedness, it need only be added that 
so far as concerns the use of the percentage definition for 
fixing the borderline in any particular system of tests the 
percentages chosen are not essential to the plan. The 
principles of the method apply whatever percentages 
might be adopted. For such important purposes as 
the comparison of the relative frequency of deficiency 
in different social groups and harmonizing the investiga- 
tions with different mental scales, agreement upon a par- 
ticular percentage is not essential. In diagnosis, of 
course, it is a matter of fundamental importance in order 
that injustice may not be done individuals. For this 



PERCENTAGE INTELLECTUALLY DEFICIENT 81 

reason the estimate should be conservative, possibly more 
conservative even than our tentative 0.5% at 15 years of 
age. Any investigator who disagrees with the above 
estimates of the degree of tested deficiency justifying 
isolation may substitute X per cent, with a doubtful 
region extending Y per cent, further. Provided such a 
census were legally authorized and funds available it 
would be not impossible to get a reliable determination 
by a house to house canvass showing the number of adult 
deficients, say 21 years of age, in typical communities, 
who were not able to survive socially without assistance. 
This number would then give the key for a conservative 
percentage and the movement for early care would be 
immensely advanced. 

With the recent introduction of psychological tests 
into the cantonments of the national army, the goal of 
symptomatic borderlines as determined by objective 
tests seems to be almost at hand. Since the men are 
brought practically at random to the camps by the draft 
and are under military command, it may be possible to 
find out the social history of a large enough group at the 
lower limit of tested ability to establish the question of 
the necessary capacity for independent moral and social 
survival. These borderlines could then be transferred 
from the army tests to positions of equivalent difficulty 
in other test systems. 

The remainder of this study will show some of the ad- 
vantages of the percentage definition for fixing the border- 
lines with a system of tests and the result of applying such 
an interpretation to the particular problem of delinquency. 
The advantage in increased definiteness should already 
be evident. When a person is classed as presumably de- 
ficient it will mean that he is in the lowest 0.5% in in- 
tellectual development or within the lowest 1.5%, if he 
is a persistent delinquent. 



CHAPTER V. ADAPTING THE PERCENTAGE 
DEFINITION TO THE BINET SCALE 

Sufficiently large random groups have not been tested 
with any development scale to make the determination of 
the borderline on the scale more than tentative. Such 
borderlines must be looked upon as temporary descrip- 
tions to be used in aiding diagnosis until more data are 
available. Nevertheless, the percentage method of pro- 
cedure seems to be an improvement over other plans of 
stating the borderline. So far as the Binet 1908 scale is 
'concerned, when we supplement Goddard's results with 
1500 school children by the data for the lower limits of a 
random group of 653 15-year-olds which we tested, the 
limits on the scale for passable intellects defined by the 
percentage method will be found, I believe, not only more 
conservative, but more reliable than those in current use. 
Moreover the intended meaning of such borders becomes 
clear. 

A. The Border Region for the Mature. 

(a) Indication from a random group. 

The passing limit for adults is unquestionably much 
more important than that for children since any child 
who once passes this limit is assured, generally speaking, 
of social fitness so far as intellect is concerned. He has 
attained a position intellectually which is sufficiently 
good to enable him to get along without social assistance 
unless he is especially deficient in will. This borderline 
for the mature has been so thoroughly neglected that in 
none of the common published forms of the Binet scale, 
except the new Stanford Scale, is there an attempt to de- 
fine it. This seems almost incredible in view of the general 
use of the Binet method in diagnosing feeble-mindedness. 
To be sure, there are discussions of this upper limit, as 
we shall see, but they have usually not been embodied 

(82) 



ADAPTING PERCENTAGE TO BINET SCALE 83 

in the actual directions accompanying the scales which 
get into the hands of amateurs. Most of these directions 
content themselves with describing borderlines for chil- 
dren with no caution about the final lower limit for social 
survival. 

The borderline for the mature is the first difficulty 
which a court examiner will encounter when he attempts 
to obtain assistance from an objective system of measure- 
ment. Very little experience will convince one that it 
is not enough to describe the deficient ability of an adult 
in terms of years of retardation. It is widely agreed that 
at some age during adolescence practically all the mental 
processes are available that will be found in the mature. 
From that time the advance in ability is made by attain- 
ing greater skill in specific activities through training 
and by increasing knowledge, rather than through a 
native change in the form of thinking. If mental tests 
mainly reach capacity for thinking, as they aim to do, 
rather than amount of knowledge or skill in specific work, 
then we are conservative in using a randomly selected 
group at 15 years of age for approximating the borderline 
on the scale for the mature. 

In connection with the new Stanford Scale, Terman 
says: "Native intelligence, in so far as it can be measured 
by tests now available, appears to improve but little after 
the age of 15 or 16 years. It follows that in calculating 
the I Q (intelligence quotient) of an adult subject, it will 
be necessary to disregard the years he has lived beyond 
the point where intelligence attains its final development. 
Although the location of this point is not exactly known, 
it will be sufficiently accurate for our purpose to assume 
its location at 16 years" {57, p. 140). 

Yerkes and Bridges in connection with their Point 
Scale say, "it seems highly probable that the adult level 



84 DEFICIENCY AND DELINQUENCY 

is attained as early as the sixteenth year" (225, p. 64). 
Kuhlmann (138) used 15 years as the divisor in calcu- 
lating the intelligence quotient of adults and Spearman 
thinks that the limit of native development is reached 
about 15 years (184). He says, 'That mental ability 
reaches its full development about the period of puberty 
is still further evidenced by physiology. For the human 
brain has been shown to attain its maximum weight be- 
tween the ages of 10 and 15 years" (184). For the last 
statement he quotes Vierordt. On the contrary Wallin 
thinks that we need more evidence for the correctness 
of these hypotheses before choosing a fixed age as a divisor 
for adults (215, p. 67). 

We arfe not interested in determining a divisor for an 
adult intelligence quotient but in fixing a conservative 
borderline for the mature. Admitting that the mental 
capacity of those 15-year-olds at the lower limit may not 
be like adults, nevertheless adults would be more likely 
to be better than worse. Borderlines for the 15-year-olds, 
should, therefore, be safe for adults. Moreover, the lower 
limits with a truly random group of 15-year-olds would 
probably be more reliable than an assorted group of 
adults subjectively chosen from different walks in life 
and combined in an effort to represent a random mature 
group. The Stanford Scale utilizes such combination of 
selected adults. It seems, therefore, that we are justified 
in utilizing the lowest percentages of randomly selected 
15-year-olds as a reasonable criterion for describing the 
limits for adult deficiency. Surely adults below this 
lower limit for 15-year-olds would have questionable 
intellectual capacity. 

The borderline for the mature being the crucial feature 
of a developmental scale when used for detecting feeble- 
mindedness, it seemed imperative to us that some effort 



ADAPTING PERCENTAGE TO BINET SCALE 85 

should be made to obtain records with a random group of 
older-age children or adults. Goddard's results with 
school children were not significant above eleven years 
of age since the personal examinations were confined to 
children in the sixth grade or below. The twelve year 
old group in the sixth grade clearly omits the best 12- 
year-olds, so that the percentage method would have no 
significance applied to his figures for children above 11 
years of age. Moreover it was obvious that the group of 
public school children 15 years of age or older would not 
give a picture of the lower end of a random group since 
many children drop out of school at 14. On the average 
those that leave are undoubtedly of lower ability than 
those who remain. 

The most valuable data on the borderline for the mature 
would come from mental examinations of large random 
groups of adults. The impossibility of gaining the con- 
sent of adults for such examinations puts this plan out 
of consideration. Perhaps the next best method would 
be to examine all the children of 15 and 16 years of age in 
typical communities. It happened that we could approach 
this result in Minneapolis since we there had an excellent 
school census made from house to house covering all 
children under 16 years of age. The Minnesota law re- 
quires school attendance until 16 years of age unless the 
child has graduated from the eighth grade. Under the 
able direction of Mr. D. H. Holbrook of the attendance 
department the census of children of school age had been 
made with unusual care. All the children living in each 
elementary school district in the city were listed in a card 
index regardless of whether they were attending public, 
parochial or private schools, or had been excused from 
attendance for disability or for any other reason. Since we 
only needed to be sure to examine the lowest few per cent 



86 DEFICIENXY AND DELINQUENXY 

of the children in ability this group of 15-year-olds could 
be tested by examining all those children in typical school 
districts in the city who had not graduated from the eighth 
grade. A third of the 15-year-olds were still in the eighth 
grade or below. Neither the compulsory attendance law nor 
the census would have reached the 16-year-old adequately. 
In most states even the 15-year-olds would have been 
above the compulsory school age. 

There were 653 children, (322 boys,) 15 years of age 
living in the seven typical districts which were selected 
objectively for study. Among these there were 196 who 
had not graduated from the eighth grade. All of these 
latter children were examined, except one who could not 
be tested as she was in a hospital on account of illness. 
Quite a number of the children were in parochial or pri- 
vate schools, two were followed to the state industrial 
school and a number were examined at home. In order 
to be sure that we had not missed any institutional cases 
in these districts the complete list of Minneapolis chil- 
dren at the State School for Feeble-Minded was gone 
through to get any of low ability who might have been 
missed. 

The seven districts in which the children were to be 
studied were chosen, with the idea of avoiding any per- 
sonal bias in their selection, by taking them alphabetically 
by the name of the schools, except that no district was 
taken where the normal school attendance of the district 
was affected by inadequate school facilities so that chil- 
dren had to be transferred either to or from that district 
to other schools in order to meet crowded conditions. 
It happened fortunately that none of these schools repre- 
sented extreme conditions in the city. The average per- 
centage of children in the 69 elementary schools of the city 
retarded in school position below a standard of 7 years in 



ADAPTING PERCENTAGE TO BINET SCALE 87 

the first grade, 8 in the second, etc., was 24.1% with a 
mean variation of 6.5%. The percentages retarded in 
the schools studied were as follows: Adams, 22.7; Bry- 
ant, 21.1; Calhoun, 21.7; Corcoran, 29.4; Douglas, 20.4; 
Garfield, 18.6; Greeley, 26.4. 

Kuhlmann's adaptation of the 1911 scale (135) was 
used as a basis for the examinations, supplemented by 
the 1908 scale wherever tests had been changed so that 
other forms of the tests were found in either Kuhlmann's 
(136) or Goddard's (110) adaptations of the 1908 scale. 
Since test results with the 1908 scale provide the most 
data for describing the borderline for the immature, our 
plan was to use the 1908 form of a test first when the pro- 
cedure had changed. The supplementary directions were 
arranged for each age so that the testing could proceed 
methodically and the results be scored under either the 
1908 or 1911 scale with the least possible disturbance of 
each test. Over a third of the children were tested by 
myself. The rest were tested by three advanced students 
in psychology. It is a pleasure to express my thanks to 
these assistants, Miss Rita McMullan, Miss Lucile New- 
comb and Miss Florence Wells. Besides having had brief 
experience in dealing with exceptional children, they 
practised testing under my observation until the tests 
could be given smoothly and I was convinced of their 
ability to follow directions intelligently and make full 
records with reasonable accuracy. The results of the 
tests were all carefully gone over and scored by me. So 
far as I can judge, the results are quite as accurate as any 
other published tables, although one must always con- 
sider the possible effect of errors of testing. Separate 
rooms were provided at the schools or homes so that the 
child could be alone with the examiner during the testing. 

In attempting to define the borderlines on these scales 



88 DEFICIENCY AND DELINQUENCY 

we might either state the exact scale position in tenths of 
a year below which 0.5 and 1.5% of the cases fall, or we 
might merely attempt at present to state the borderlines 
in rounded terms of years on the scale. The latter plan 
is the one I have adopted for several reasons. The main 
reason is that I wish to emphasize that these are still 
rough boundaries. Besides that, however, a study of 
the results shows that the cases do not distribute by sep- 
arate tenths of a year so that exactly these percentages 
could be picked off, without a questionable smoothing of 
the curves while the rounded years approach these limits 
fairly well. 

It seems to me that it is best at present to be carefully 
conservative in describing these borderlines, so that I 
have chosen them from the available data at the nearest 
rounded age position which is reasonably sure not to 
catch more than these limiting percentages. Throughout 
the tables I have also followed the published directions 
for the 1908 scale in classing the person in the intellectual 
age group in which he finally scores all or all but one of 
the tests. I recognize, of course, that this is an arbitrary 
limit; but it is the limit fixed by the usual printed directions 
going with the 1908 scale, which is the only one thus far 
standardized for the immature on the percentage basis. 
For those who wish to calculate other borderlines or re- 
construct the individual tests of the scale I have provided 
the complete data for each individual both for the 1908 
and 1911 scales in Table XXI, Appendix I. The table 
also gives the exact ages and school grades of each child. 

The summary of the results with the tests for those 
testing under XII is given in Table III. Life-age* at 

Throughout this study I shall use the literal translation of the Ger- 
man term "lebensalter," life-age, instead of the awkward "chronological 
age." 



ADAPTING PERCENTAGE TO BINET SCALE 



89 



the last birthday and not the nearest life-age is used in 
the table. The children were all between their 15th and 
16th birthdays. Following the directions published with 
the scales, the basal age for calculating the results in the 
table is taken as the highest at which all or all but one 
test are passed for the 1908 scale, and the highest at which 
all were passed for the 1911 scale. Two-tenths is allowed 
in the table for each test passed above the basal age and 
0.1 for an uncertain answer. The children were tested 
by the long method, beginning with the mental-age group 
at which the child could pass all the tests and continuing 
to that age group in which he failed in all. 

TABLE III— Test Borderlines with Randomly Selected 

Minneapolis 15-year-olds 

Percentages of 653 living in these districts , 196 of whom had not graduated 

from the eighth grade and were tested. Scored by the Kuhlmann and 

Goddard 1908 Binet scale and by the Kuhlmann 1911 scale. 





1908 Scale 


1911 S 


^ale 


Scored below 


Pass all but one in basal age 


Pass all in 1 
Per cent. 


jasal age 




Per cent. 


Cases 


Cases 


IX. 


0.0 





0.0 





IX. 8 


0.2 


1 


0.5 


3 


X.O 


0.3 


2 


0.5 


3 


X.8 


1.1 


7 


1.2 


8 


XI. 


1.2 


8 


2.0 


13 


XI. 8 


10.0 


65 


8.1 


53 


XII. 


10.4 


68 


13.0 


85 


XII. 8 


23.6 


153 


29.1 


190 


XIII or XV 


23.6 


153 


29.7 


194 



Thrown into percentages of the group of 653 children 
living in these districts, it is evident that a test score of XI 
raises any person above the group of intellectual deficients. 
The percentage that tested this low, i. e., under XI.8, 
with the 1908 scale, was 10.0 (65 cases) and this would 
probably be increased if those who had graduated from 



90 DEFICIENCY AND DELINQUENCY 

the eighth grade had also been tested. The percentage 
testing under the same position in the 1911 scale is 8.1 
(53 cases). With the 1911 scale there were 32 additional 
cases testing XI. 8 or XI. 9. The table indicates that 
0.2% of the 15-year-olds tested below IX.8 with the 
1908 scale, and 0.5% with the 1911 scale. This defines 
our scale borderline for the mature who are presumably 
deficient as below test-age X. These positions are near 
enough to the lowest 0.5%. The group testing of un- 
certain ability, age X, (strictly speaking between IX.8 
and X.7 inclusive,) includes 0.7 to 0.9%. We thus ap- 
proach fairly well the rounded age positions which ex- 
clude 1.0% above the lowest 0.5%. The total number 
testing in presumably and uncertain groups is thus 1.1%, 
7 cases out of 653, for the 1908 scale and 1.2%, 8 cases, 
for the 1911 scale. This is to be compared with the per- 
centage definition that the lowest 1.5% are either presum- 
ably deficient or uncertain. 

At present we are entitled to assume that adults testing 
below XI, i. e. y below X.8, are so low in intellectual de- 
velopment that it is a question whether they have suffic- 
ient equipment to survive socially. Fine discriminations 
with the Binet scale are not possible with our present 
knowledge. So far as our information goes, if we use the 
percentage method of defining intellectual deficiency, we 
may say that adults who test X are in an uncertain .group 
in intellectual ability, with the probability that they 
will require more or less social care, while those who test 
IX are deficient enough to need continuous care unless 
the evidence of the test is contradicted by other facts or 
is accounted for by the existence of removable handicaps. 

It is perhaps not necessary to call attention to the fact 
that X and XI are used here merely to refer to positions 
on the Binet scale without regard to what per cent, of 



ADAPTING PERCENTAGE TO BINET SCALE 91 

ordinary 10-and- 11 -year-old children attain these posi- 
tions. For example, XI does not imply that most of the 
children of eleven years of age are above this borderline. 
Table IV, to be given later, suggests that hardly two-thirds 
of random 12-year-old children pass this position on the 
1908 scale and not half of the 11-year-olds. Thorndike 
regarded X.8 as normal for a child of 11.6 years of age. 
(200) 

So far as the determination of intellectual deficiency is 
concerned we should note with emphasis that placing the 
limit of passable intellects at XI for adults almost en- 
tirely removes the common objection to the Binet scale 
on account of the difficulty of the older age tests. The 
older age tests become of little consequence because the 
best of the deficient group have a chance at tests in at least 
two groups above those of mental age X, so that they can 
increase their score by passing advanced tests as they 
could not if they had to test XII. 

As a check upon the borderline for those presumably 
deficient, it is important to note that the only case which 
tested below this borderline with the 1908 scale was a 
girl in the 4B grade. She tested exactly IX with each 
scale and was the only child in the group who was below 
the fifth grade in school. There can be no question that 
she was mentally deficient. On the other hand in the 
group which tested X or above there are several cases 
which it would be unjust in my opinion to send to an 
institution for the feeble-minded without some other 
evidence of mental weakness. Half of them, for example, 
are in the seventh grade. In Minneapolis this is not as 
significant as it might be in other cities, since pupils are 
rarely allowed to remain more than two years in the same 
grade whether they are able to carry the work of the 



92 DEFICIENCY AND DELINQUENCY 

next higher grade or not. Pupils in higher grades may 
not always be able to do even fifth grade work. 

The evidence from the institutions for the feeble-mind- 
ed indicates that less than 5% of their inmates test XI 
or over. Of 1266 examinations at the Minnesota School 
for Feeble-Minded, 3.8% (154); of 378 examined at 
Vineland, 3.2% (113); of 140 consecutive admissions 
examined by Huey at Illinois, 5.7% (129). To be sure, 
a goodly number of these inmates are not eleven years of 
age, but a majority of them are at least that old and many 
are older. Of 280 children in the Breslau Hilfsschulen, 
Chotzen (89) found none reaching XI, and only six who 
tested X. These few cases in institutions reaching XI 
or over may well come within our class of those feeble- 
minded through volitional deficiency. 

Goddard's description of the children at the Vineland 
school for feeble-minded who tested XI with the 1908 
scale hardly sounds like an account of social deficiency. 
He says: 

"In the eleven year old group we find only five in- 
dividuals, but they are children who, for example, can 
care for the supervisor's room entirely, can take care of 
animals entirely satisfactorily, and who require little or 
no supervision. They are, it is true, not quite as expert 
or trustworthy as those a year older, and yet the differ- 
ence is very little and the two ages can probably be very 
well classed together" (113). 

The studies of groups are more important for fixing our 
general rules than individual examples. -We must al- 
ways expect to find exceptional cases where the brief in- 
tellectual tests given in an hour or less are not adequate, 
especially if the testing has been interfered with by the 
person's emotional condition at the time or by deliberate 
deception. A number of illustrations have been reported 



ADAPTING PERCENTAGE TO BINET SCALE 93 

of successful adults who have tested X under careful ex- 
aminations. Such, for example, are three cases of suc- 
cessful farmers tested by Wallin (215) and a normal 
school student tested by Weidensall (59). There are 
two examples of persons testing IX with the Binet scale 
and yet earning a living. Such is the case related by 
Dr. Glueck of the Italian immigrant making two trips to 
this country to accumulate wealth for his family by his 
labor (109) , and the case of the boy reported by Miss 
Schmidt (179). These cases should make us cautious, 
but they are so rare that it seems best to treat those test- 
ing IX at least as exceptions. 

The group studies confirm our suggestion that a border- 
line of X or below will bring in for expert consideration 
nearly all adults who are feeble-minded from a lack of in- 
tellectual ability, while testing IX is a fairly clear indica- 
tion of such serious deficiency as to justify isolation. 
That testing X, in the absence of other evidence of cona- 
tive disturbance, places the case only in an uncertain 
region so far as isolation is concerned is best indicated by 
the fact that 1.1% to 1.4% of these 15-year-olds tested 
this low. We have good evidence that many in special 
classes, which contain only about the lowest one per cent., 
afterwards do float in society with or without social 
assistance. They cannot be presumed to require isola- 
tion, as I showed in the previous chapter. It is better to 
say at present that those testing X require evidence of 
their deficiency before isolation, except in special classes, 
is justified. The test diagnosis alone is too uncertain, even 
when there are no removable handicaps. 

As to the reliability of these borderlines, too much em- 
phasis can hardly be put upon the fact that they have 
been determined for only a single group of 653 in a single 
community. They are undoubtedly not the exact border- 



94 DEFICIENCY AND DELINQUENCY 

lines, although they are the most probable percentage 
estimates we have at present and were obtained in a 
group that was as nearly unselected as it is possible to 
obtain. The method of selection was perfectly objective 
and excluded no feeble-minded children of this age living 
in these school districts. 

The theory of sampling applied to percentages (228) 
enables us to say that the standard deviation of the 
true lowest 0.5% in samples of this size made under the 
same conditions would not be more than 0.28%.* That 
is to say, if our result were only affected by the size of our 
sample the chances are about two out of three that the 
border of the true lowest 0.5 per cent, would lie between 
the border of the lowest 0.22% and the lowest 0.78% of 
a very large sample. Assuming that the distribution in 
this sample represented that of communities generally, 
the chances would be two out of three that the true border 
of the lowest 0.5% for like groups in like communities 
examined under the same conditions would lie between 
IX.O and X.6 or X.4 on the 1908 and 1911 scales respec- 
tively. Moreover, the chances that a case in the lowest 
0.5% in this sample would be above the doubtful group in 
a larger sample, i. e., get above the lowest 1.5%, would 
be about 1 in 10,000. On the other hand, the chances 
that a case above the true lowest 1.5%, L e., above the 
uncertain group, would get into the lowest 0.5% in a 
larger sample, i. e., be classed as clearly deficient intel- 
lectually, would be about 18 in 1,000. 

So far as the theory of sampling goes it would seem 
that these borderlines for the mature are sufficiently ac- 
curate for correcting present practise. On the other 
hand, the conditions in Minneapolis so far as deficiency 



¥ S.E. 



> n 



ADAPTING PERCENTAGE TO BINET SCALE 95 

is concerned are probably better than in the country as 
a whole, so that the borderlines here described might very 
well exclude more than the lowest 0.5% and 1.5% in the 
country at large. But if we shifted the definition so as 
to exclude the lowest 0.2% and 1.1% (the percentages 
empirically found below the limits described), the borders 
on the Binet 1908 scale would not be changed from the 
rough measures IX and X which are as accurate as we 
should expect to define our limits with the present data. 

(b) THE PRESENT TENDENCY AMONG EXAMINERS. 

Comparing the suggestions as to the borderline for the 
mature which have heretofore been made, we find that 
they have gradually approached the boundary now sug- 
gested by the percentage method. In 1910 the Amer- 
ican Association for the Study of the Feeble-Minded 
adopted a tentative classification in which the upper 
limit of the feeble-minded included those "whose mental 
development does not exceed that of a child of about 
twelve years' ' (64). This was based mainly on the fact 
that Goddard had found no case at the Vineland school 
for feeble-minded which tested higher than XII. Huey 
later than this found only two such cases at the institution 
at Lincoln, 111., and Kuhlmann only ten cases at the Min- 
nesota State School for the Feeble-Minded. 

There was an early statement by Binet which referred 
to the practise in Belgium of regarding older school chil- 
dren as deficient when they were three years retarded in 
their school work (77, p. 41). This practise may have 
also contributed to this formulation by the American 
Association. Binet, however, regarded a child of the 
mentality of twelve as normal. In 1905, before his tests 
were arranged in age groups, he said: 

"Lastly we have noticed that children of twelve years 
can mostly reply to abstract questions. Provisionally 



96 DEFICIENCY AND DELINQUENCY 

we limit mental development at this point. A moron 
shows himself by his inability to handle verbal abstrac- 
tions; he does not understand them sufficiently to reply 
satisfactorily ,, (76, p. 146). 

It is important to consider how the suggestion of XII 
as the upper limit of feeble-mindedness for adults got into 
the early practise in this country as the lower borderline 
for the mature. It is the most serious error which has 
marred investigations in this field. It seems to have been 
a case of repeated misunderstanding on the part of ex- 
aminers for which nobody in particular was to blame. 
So far as I can determine nobody stated directly in con- 
nection with any scale what should be regarded as the 
lower borderline for the mature. Numerous examiners, 
however, in reporting their results, concluded that if the 
feeble-minded tested as high as XII then adults who 
tested XII were feeble-minded. They were somewhat 
encouraged in this fallacy by the fact that the 1908 scales 
suggested three years of retardation as an indication of 
feeble-mindedness, and the highest age-group of tests was 
soon shifted to fifteen years. 

The trouble seems to have been that early workers failed 
to recognize that some of the feeble-minded in institutions, 
the purely conative cases, have passable capacity so far 
as the brief intellectual tests are concerned. To deter- 
mine scientifically what is the borderline, we should study 
randomly selected groups from the general population 
and determine the positions on the scale below which 
practically all are socially unfit. Or, as Wallin has sug- 
gested, we should find out the degree of tested ability 
necessary for survival in simple occupations that are af- 
forded by society (216, p. 224). These positions can only 
be checked by finding the conditions in institutions or 
special classes. They cannot be determined by tests of 



ADAPTING PERCENTAGE TO BINET SCALE 97 

these abnormal groups alone. Besides the confusion 
arising from these feeble-minded who are primarily un- 
stable or inert, but with passable intellects, reasoning from 
the statistics on abnormal groups merely repeats a com- 
mon fallacy. The fact that some inmates of institutions 
test XII does not let us know how many outside the in- 
stitutions who test XII actually survive in society. 

The randomly selected groups of children on which 
Binet tried out his tests were so ridiculously small that he 
continually cautioned against adopting his suggestions 
as to borderlines as anything but tentative. For judging 
the borderline for the mature there were no test results 
which had not been seriously affected by the methods of 
selecting the groups, so we collected the data on this 
random group of Minneapolis 15-year-olds. I trust that 
this will make any examiner more careful about assuming 
that adults testing XI are clearly unable to survive so- 
cially, unless he is ready to claim that 10% of the general 
population are unfit socially. 

It is to be noted that, taken literally, the description of 
the American Association is not in terms of the Binet 
scale, but of the mental development of a normal child of 
twelve years, although the framers of the resolution un- 
doubtedly had the Binet scale of mental ages in mind. 
It was soon found that the tests for the older ages in the 
Binet 1908 scale were too difficult for the places assigned 
them. This is certainly true with the tests for twelve 
years and probably with those for eleven. This evidence 
is assembled in Table IV. The combined results should 
be used only with great caution since the methods of the 
investigators differed in detail and the groups were dif- 
ferently chosen. In the groups of children which Bober- 
tag and Bloch and Preiss tested, there had been eliminated 
some of those who were backward in school, while God- 
dard's group did not include the best 12-year-olds. 



98 



DEFICIENCY AND DELINQUENCY 



TABLE IV 

Results with the Binet Tests for Mental Ages XI and XII 
(1908 Series) 





No. of 
Cases 


Pass tests 

XII 
or better 


Pass tests XI or better 


Investigators 


Life-Age 

12 11 

No. No. 


Life- Age 
12 

No. % 


Life- Ages 




11 
No. 


% 


12 

No. % 


Binet and Simon 
(School m poor 

quarter) 
1908 study 

1911 study 


11 
23 


20 


2 18 


13 


65 


7 
15* 


64 
65 


Bloch and Preiss 
(Only pupils up 
to grade) 


21 


15 


21 100 


13 


87 


21 


100 


Bobertag 
(Pupils averaged 
satisfactory) 


33 


34 


19 57 


18 


53 


29 


88 


Dougherty 
(Includes 8th grade) 


46 


44 


9 20 


22 


50 


36 


78 


Goddard (Includes 
none above 
6th grade) 


144 


166 


39 27 


73 


44 


75 


52 


Johnston (Includes 
some high- 
school pupils) 


24 


29 


6 25 


7 


24 


? 


Terman and Childs 
(Includes a 
few in 8th 
grade) 


35 


44 


3 9 


14 


32 


29 


83 


Rogers and Mclntrye 


20 


27 


1 5 


6 


22 


5 


25 


Totals 


357 


379 


100 


166 .. 


217? . . 



*Tests XI were recorded as XII in the 1911 series. 



ADAPTING PERCENTAGE TO BINET SCALE 99 

Binet and Simon. L'Annee Psychol., 1908, 14: 1911, 17: 145-200. 
Bloch and Preiss. Zeits. f. angew. Psychol., 1912, 6: 539-547. 
Bobertag. Zeits. f, angew. Psychol., 1912, 6: 495-538. 
Dougherty. J. of Educ. Psychol., 1913, 4: 338-352. 
Goddard. Ped. Sem., 1911, 18: 232-259. 
Johnston. J. of Exper. Ped., 1911, 1: 24-31. 
Terman and Childs. J. of Educ. Psychol., 1912, 3: (Feb.-May). 
Rogers and Mclntyre. Brit. J. of Psychol., 1914, 7: 265-299. 

Each of the studies indicated in the table, except that 
of Bloch and Preiss, gives evidence that the XH-year tests 
are too difficult for 12-year-old children. Moreover, we 
find that in the 1911 revision of their scale Binet and Simon 
advanced their 1908 XH-year tests to test-age XV and 
four out of the five Xl-year tests to test-age XII. Pass- 
ing the XH-year (1908) tests would, therefore, seem to 
bring a child above the upper limit of feeble-mindedness 
as defined even by the American Association for the 
Study of Feeble-mindedness, since it means more than 
the intelligence of a child of 12. 

Goddard still adhered to this borderline of the Amer- 
ican Association in 1914 in his work on Feeble- 
Mindedness. He says: "We have practically agreed to 
call all persons feeble-minded who do not arrive at an 
intelligence higher than that of the twelve year old normal 
child" (p. 573). In the same year Schwegler's ' Teachers' 
Manual" for the use of the Binet scale says that a person 
who tests XII is a moron if mature (180). Since the evi- 
dence of Table IV indicates that 75% of the twelve-year- 
olds do not test above XI, even those who adhere to the 
high limit of the intelligence of a 12-year-old should have 
required an adult to test XI on the Binet scale in order 
to show deficiency. 

In 1911 we find Wallin writing, regarding the 1908 tests, 
"it is a question whether the line of feeble-mindedness 



100 DEFICIENCY AND DELINQUENCY 

should not be drawn between eleven and twelve instead 
of between twelve and thirteen. ... A number of 
our twelve-year-olds are certainly very slightly, if at all, 
feeble-minded" (210). Jennings and Hallock (31) and 
Morrow and Bridgman (39) in testing delinquents re- 
ported in 1911 and 1912 that they regarded those passing 
the tests for twelve years as socially fit. Chotzen (31) 
thinks that the two children in his group of pupils from a 
Hilfschule who test ten and are three years or more re- 
tarded are not feeble-minded. Davis thinks that those 
"showing mentality from ten to twelve years' ' may pos- 
sibly not be called mentally defective (133 y p. 187). 

In 1915 the editors of the magazine ' 'Ungraded' ' in their 
recommendations regarding the use of the Binet scale 
say "a mental age of 10 or above is not necessarily indi- 
cative of feeble-mindedness, regardless of how old the 
examinee may be" (66, p. 7). In the same year Kohs, in 
reporting the examinations of 335 consecutive cases at 
the Chicago House of Correction, says: "We find normal- 
ity to range within the limits 12 2 and 10 4 and feeble- 
mindedness not to extend above the limit ll 2 . In other 
words, none of our cases testing ll 3 or over was found, 
with the aid of other confirmatory data, to be mentally 
defective. None of our cases testing 10 8 or below was 
found to be normal. Of those testing between 10 4 and 
ll 2 , our borderline cases, a little less than half were found 
normal, and somewhat more than half were found feeble- 
minded' ' (33). His exponents here refer to number of 
tests and not to tenths of a test-year. Hinckley (182) re- 
ports examinations with the Binet 1911 scale on 200 con- 
secutive cases at the New York Clearing House for Mental 
Defectives which show that with these suspected cases, 
which were from 13 to 43 years of age, seven-eighths tested 
X or below. Referring to adults, Wallin states that he 



ADAPTING PERCENTAGE TO BINET SCALE 101 

has "provisionally placed the limen somewhere between 
the ages of IX and X" (215). Dr. Mabel Fernald at the 
Bedford Reformatory laboratory said in 1917, "many of 
us for some time have been using a standard that only 
those who rank below ten years mentally can be called 
feeble-minded with certainty" (16). The reader should 
also see the admirable review and discussion of the border- 
lines on the Binet scale in Chap. II of Wallin's Problems 
of Subnormality. Two descriptions of the scale border- 
lines in books on mental testing which appeared in 1917 
are of interest. In his Clinical Studies in Feeble-Mind- 
edness (p. 76), E. A. Doll says: 

"By the Binet-Simon method feeble-mindedness is 
almost always (probably more than 95 times in a hundred) 
an accurately safe diagnosis when the person examined 
exhibits a mental age under 12 years with an absolute 
retardation of more than three years, or a relative re- 
tardation of more than 25 per cent." 

N. J. Melville, in his Standard Method of Testing Ju- 
venile Mentality (p. 10), says: 

"Conservative estimates today place the upper limit 
of feeble-mindedness at least in a legal sense at Binet age 

ten; others place it at Binet age eleven 

A Binet age score below eleven whefi accompanied by a 
sub-age (retardation) of more than three years is usually 
indicative of serious mental deficiency. Even when ac- 
companied by a slight sub-age score, a Binet age score be- 
low eleven may be indicative of potential mental deficiency 
when the test record reveals a Binet base that is six or 
more years below the life age." 

In 1916 the new Stanford scale appeared and its tests 
a*e arranged so that approximately 50% of each age in- 
stead of 75%, test at age or above. Even with this low- 
ering of the scale units, Dr. Terman describes his borderline 
for "definite feeble-mindedness" as below an intelligence 



102 DEFICIENCY AND DELINQUENCY 

quotient of 70. This would mean for his 16-year-old 
mature borderline a mental age on this scale of XI.2. We 
have no means of determining to what positions these 
points on the Stanford scale would correspond on the 1908 
or 1911 Binet scales. Dr. Terman says "the adult moron 
would range from about 7-year to 11-year intelligence" 
(57). Apparently also referring to the Stanford scale, 
the physicians at the Pediatric Clinic of that university 
agree with this borderline and say: "morons are such 
high grade feeble-minded as never at any age acquire a 
mental age greater than 10 years" (169). That there is 
still need for more caution is evidenced by the statement 
of a prominent clinician in 1916 that "cases prove ulti- 
mately to be feeble-minded since they never develop be- 
yond 12 years intelligence" (135). 

Most interesting perhaps is the fact that Binet and 
Simon themselves, the collaborators who first formulated 
the scale for measuring intelligence by mental ages, after 
their years of experience with the tests came, by rule of 
thumb, to regard IX as the highest level reached by those 
testing deficient. Dr. Simon stated the borderline for 
the mature in this way in a paper read in England in 1914 
and published the next year. He said: 

"Provisionally it might be proposed to fix at 9 years the upper level 

of mental debility We have reason to think that a 

development equivalent to the normal average at 9 years of age is the 
minimum below which the individual is incapable of getting along 
without tutelage in the conditions of modern life. A certain number of 
facts suggest this view and are mutually confirmatory. Nine years is 
the intellectual level found in the lowest class of domestic servants, in 
those who are just on the border of a possible existence in economic in- 
dependence; it is, on the other hand, the highest level met with in gen- 
eral paralytics who come under asylum care on account of their de- 
mentia; so long as a general paralytic, setting aside any question of 
active delirious symptoms, has not fallen below the intellectual level 
of 9 years, he can keep at liberty; once he has reached that level, he 



ADAPTING PERCENTAGE TO BINET SCALE 103 

ceases to be able to live in society. And lastly, when we examine in 
our asylums cases of congenital defect, brought under care for the sole 
reason that their intelligence would not admit of their adapting them- 
selves sufficiently to the complex conditions of life, we find that amongst 
the most highly developed the level of intelligence does not exceed 
that of a normal child of 9 years of age" (182). 

In connection with their 1911 revision of the scale Binet 
and Simon had stated that among 20 adults in a hospital 
where custodial care was provided for the deficient "we 
found that the best endowed did not surpass the normal 
level of nine or ten years, and in consequence our measur- 
ing scale furnished us something by which to raise before 
them a barrier that they could not pass" (79, p. 267). 
They, however, then expressed complete reserve as to the 
application of this criterion to subjects in different en- 
vironments on their presumption that deficiency for the 
laboring class is different from that for other classes in the 
population. 

The Germans seem to have early recognized a lower 
borderline for the mature than we did in this country for 
we find Chotzen saying in 1912 that he agreed with Binet's 
finding that "idiots do not rise above a mental age of three, 
imbeciles not over seven, and debile not over ten" (89, 
p. 494). Stern also quotes Binet as declaring that the 
moron does not progress beyond the mental age of nine 
(188, p. 70). 

The tendency of interpretation indicated by these 
studies is plainly to lower the borderline for passable 
mature intellects until it approaches the limits which the 
percentage definition suggests as reasonable from our 
available evidence. The percentage plan thus confirms 
the borderline that has been approached gradually by hit 
or miss methods. An adult testing IX is presumed de- 
ficient, while one testing X is in an uncertain zone. The 



104 DEFICIENCY AND DELINQUENCY 

numerous studies of delinquents which have regarded 
adults who tested XI and even XII as deficient have ser- 
iously overestimated the problem of the deficient delin- 
quent, as we shall see in our later chapter on tested de- 
linquents. 

B. The Border Region for the Immature. 

(a) FOR THE BINET 1908 SCALE. 

In attempting to adapt the percentage method of des- 
cription to the border region for the immature, it is es- 
sential that the tests shall have been tried out on randomly 
selected groups. Neither teachers nor the examiner 
should pick out children to be tested, if we are to know much 
about the region of lowest intellects. While Bobertag's 
method of choosing typical groups by balancing those 
backward in school by those advanced, is serviceable for 
his purpose of determining norms, the personal element 
of choice involved makes the results thus obtained almost 
useless in determining the lower limit of ability. 

In regard to the diagnosis of intellectual deficiency by 
the Binet 1908 or 1911 scales, we know much more about 
the interpretation of results obtained with the 1908 scale 
than with the 1911 scale. The 1908 scale was therefore 
used for our examinations of juvenile delinquents. The 
best available data on which to base a description of the 
borderline for the immature is that collected by Goddard 
(119). He says that he "arranged to test the entire school 
population of one complete school system. This system 
includes about five thousand population within a small 
city and as many more outside, so that we have, city and 
country, a school population of about two thousand chil- 
dren .... In the seventh and eighth grammar 
grades and the high school, the children were tested in 
groups/ ' Since only the first six grades were tested in- 



ADAPTING PERCENTAGE TO BINET SCALE 105 

dividually and only these results are published in sufficient 
detail to be available, we shall confine this account to 
the school children below the seventh grade. It must be 
remembered that any children of the idiot class and pos- 
sibly some of the low imbeciles would not be included in 
his figures for they would probably have been excused from 
school attendance. In a small rural community it is not 
likely that these would be numerous enough to change the 
rough borderline materially. We thus have a fairly 
random group for a small town and its environs. 

Since we cannot use Goddard's results for our purpose 
above the sixth grade, it is plain that we would not suffi- 
ciently approach a random distribution for any age above 
11 years. In Minneapolis, for example, a recent census 
showed 28% of the public school children 12 years of age 
are in the seventh grade or above, while 6% of the better 
eleven-year-olds would be excluded by including only 
those below the seventh grade. We have therefore omit- 
ted from our calculations all of Goddard's results for 
children above eleven years of age as too unreliable for 
purposes of percentage estimations. Even his eleven- 
year-olds may be affected. 

Although it is not clear in the published reports whether 
the nearest or last birthday was used, Dr. Goddard has 
informed me that his table shows the results for ages at 
the last birthday. A child is regarded as six until he has 
reached his seventh birthday, as is customary. Through- 
out this book I have followed this method of using age 
to mean age at last birthday, or avowed age. This is in 
conformity with the common use of age and with general 
anthropometric practise. It is less confusing and less 
subject to mistake or errors of record. On the whole, I 
believe that in statistical work avowed age is preferable 
to nearest age. 



106 



DEFICIENCY AND DELINQUENCY 



TABLE V. 

Percentages of Mentally Retarded Children Tested with the 
1908 Binet Scale. {From Goddard's Table.) 





No. of 


Years Retarded 


Life- Age 


Two or 


Three or 


Four or 


Five or 




cases 


more 


more 


more 


more 


5 


114 


5.3 


1.8 






6 


160 


2.5 


0.6 


0.6 




7 


197 


5.6 


1.5 


0.5 


0.0 


8 


209 


2.4 


1.9 


1.0 


0.0 


9 


201 
222 


1.3 
18.9 


0.0 


0.0 
1.4 


0.0 


10 


8.1 


0.0 


11 


166 

1269 


25.9 


10.8 


3.0 


0.6 



In the accompanying Table V Goddard's results are ar- 
ranged so as to show the percentages at each life-age re- 
tarded two or more, three or more, four or more, and five 
or more years according to the Binet 1903 scale. The 
heavy black line indicates the upper borderline of the 
doubtful group according to our interpretation. In 
spite of irregularities, due mainly to insufficient numbers, 
the trend of the table is fairly plain. The column of per- 
centages two or more years retarded and to the left of the 
heavy line suggests that the break comes at ten years of 
age. Using our tentative criterion of 0.5% presumably 
deficient and the next 1.0% uncertain intellectually, the 
outcome of this analysis is a rather striking demonstration 
of the feasibility of the percentage procedure even when 
the groups examined at each age are only composed of 
about 200 cases. I have preferred to take the empirical 
data at the lower extreme of each age distribution instead 
of projecting the tail of a smoothed distribution curve for 
each age. 



ADAPTING PERCENTAGE TO BINET SCALE 107 

Until better data are available we have adopted in 
practise, as a result of the study of this table, the procedure 
of considering any child who is ten years of age or over as 
testing of doubtful capacity if he is four or more years 
retarded below his chronological age, three or more years 
retarded if he is under ten years of age. If he shows one 
additional year of retardation we consider, in the absence 
of some other explanation of his retardation, that he is 
presumably intellectually deficient enough to justify a 
recommendation of isolation. Of course no such re- 
commendation should be made without a complete medi- 
cal examination, a full knowledge of the history of the 
case and a checking of the record by further tests at dif- 
ferent times when there is any suspicion that the child 
has not done as well as he might under other conditions. 

The fact that we have no data on random groups 12, 
13 and 14 years of age leaves a gap which may mean that 
our criterion of 5 years retardation for presumable de- 
ficiency at these ages is too small. It is possible that the 
shift to 6 years retardation should be made before 15 
years, which is the position where our criterion for the 
borderline for the mature automatically makes the shift. 
We say a 15-year-old testing X is above the group pre- 
sumably deficient as he has entered the "doubtful" adult 
class. 

It is also to be remembered that the standard error 
expected from the results of samples as small as these is 
0.5% when the sample is 200 and 0.7% when it is 100. 
The limits thus might easily shift a year. The suggested 
borderlines for the immature can at best be regarded only 
as the most likely under the meager evidence available. 

Whether the borderlines for deficiency on the Binet 
scale should be described in terms of years of retardation 
is doubtful except, as in this case, for practical conven- 



108 DEFICIENCY AND DELINQUENCY 

ience. It is certainly only a rough indication of the bor- 
derlines. When this method has not been followed the most 
common practise is to use some form of Stern's "intelli- 
gence quotient/ ' An extended discussion of this question 
is reserved for Part II of this book, to which the reader 
is referred. It need only be said here that the percent- 
age procedure adapts itself to either method of descrip- 
tion. Since the designation of the limits must be very 
rough until we have much further information from 
tests upon unselected groups, we have adopted the com- 
mon method of description in terms of years of retarda- 
tion, since it seems to afford for the 1908 scale the simplest 
expression of the borderline until the tests have been 
much improved. It happens that the empirical results 
for 5 years of age and over lend themselves to designating 
the lowest percentages in terms of years of retardation 
with only a single shift at 9 years of age. An equally 
accurate designation by the intelligence quotient would be 
quite complicated if it were adapted equally well to the 
different life-ages. 

The fact that the Binet mental ages do not signify cor- 
responding norms at each age has been frequently pointed 
out (200). Moreover it is probable that one year of re- 
tardation on the scale means a different thing at different 
chronological ages. With the new Stanford form of the 
scale, for example, "a year of deviation at age 6 is exactly 
equivalent to a deviation of 18 months at age 9, and to 2 
years at age 12, etc." (197) when measured in terms of 
the deviation in ability at these ages. This variation 
does not interfere, however, with our use of the "years of 
retardation" merely as a short method for describing 
empirically the positions on the scale which roughly and 
conservatively designate the same percentages of children 
of low ability at various ages. Besides its convenience in 



ADAPTING PERCENTAGE TO BINET SCALE 109 

this respect, there is no question but that such a descrip- 
tion does help better than a quotient to convince the pub- 
lic of the seriousness of the deficiency. 

A more serious theoretical objection to describing the 
borderline for the immature in terms of years of retarda- 
tion is that, when one changes from three to four years of 
retardation, it is clear that a moron who tests VI at 9 years 
of age would be supposed to be still only VI at 10 years in 
order to remain below the borderline, while it is known 
that there is some, albeit a small, amount of progress made 
by the higher class deficients at these ages. In the crude 
state in which the Binet scale still remains, however, we 
have preferred to waive these theoretical objections in 
favor of the prevalent custom which has the advantages 
of simplicity, practical convenience, popular significance 
and, in this case, equal accuracy. 

It is, of course, very desirable that the results obtained 
by Goddard as well as our Minneapolis results should be 
checked by data on unselected groups elsewhere. With 
the 1908 scale the only other data which seems fairly to 
represent a random selection are those of Terman and 
Child's (195, p. 69). Since they examined less than 50 
at any age, however, their table helps only to check rough- 
ly the borderline suggested. The percentages retarded 
two years or more changed to the basis of calculation we 
used, indicate that the break comes at 10 years. The 
percentages from six up to ten years run 0, 3, 7, 6, when 
they change to 12% or more for the following ages. While 
the groups are too small to indicate the borderlines for 
each age, yet, when we group the children from 6-9 years 
inclusive, under our interpretation we find that a year 
less than our upper borderline for the uncertain group 
would give 4.8% of 147 cases. With 142 cases in the 
group 10, 11, and 12 years old, 5.6% would be caught by 



110 DEFICIENCY AND DELINQUENCY 

placing the borderline for the doubtful a year less than 
we have indicated. Our scale borderlines are thus in 
harmony with these data. 

(b) DATA FOR OTHER DEVELOPMENTAL SCALES. 

When we turn to data from randomly selected groups 
for judging the borderlines with other developmental 
scales than the 1908 Binet, we find that a group of chil- 
dren in the rural schools of Porter County, Indiana, have 
been examined with the Goddard adaptation of the Binet 
1911 scale [92) and a group of school children in a Min- 
nesota city, with the Kuhmann adaptation of the 1911 
scale (138). The important results with each study are 
given in Table VI. In the Indiana study the children 
were examined through the eighth grade. The elimina- 
tion of older children from school would certainly affect 
the groups over 13 years of age and probably disturb the 
results even for the 13-year olds. For this group the 
results are published only for nearest mental and nearest 
life-ages. The results are, therefore, not strictly com- 
parable with those of Table V. for the 1908 scale. It is 
doubtful whether tests on children in the rural schools 
should be used for indicating borderlines. The table 
suggests, however, that the borderlines we have indicated 
for the 1908 scale are not too conservative for the imma- 
ture tested with the 1911 scale. It is possible, however, 
that with Goddard's adaptation the break comes at 9 
years of age instead of 10. 

Kuhlmann, with the assistance of twenty teachers 
whom he started in the work and whom he regards as 
"untrained examiners," measured "the public school 
children from the first to the seventh grade, inclusive, in 
a Minnesota city." The essential figures from his re- 
sults are given in Table VI, These results are not directly 



ADAPTING PERCENTAGE TO BINET SCALE 



111 



TABLE VI. 
TABLE VI. — Mental Retardation of Children as Tested 

WITH THE 1911 BlNET SCALE 



Children in the Rural Schools of Porter County, Indiana, tested with the 
Goddard 1911 scale. {From Table XIII, V. S. Public Health Bul- 
letin, No. 77) 



Nearest 


Total 


Percentages showing 


the following years of 


Life- Ages 


Pupils 


tested retardation according to the nearest 






mental ages: 










Two or 


Three or 


Four or 


Five or 




107 


more 


more 


more 


more 


6 


2.8 








7 


232 


6.03 


.43 








8 


234 


8.12 


2.12 


.42- 






9 


216 


12.04 


5.54 


1.84 




92 


10 


278 


19.88 


3.58 


1.08 




36 


11 


212 


18.3 


8.4 


1.8 






12 


243 


33.9 


12.9 


2.6 






13 


249 


63.7 


27.9 


8.4 


2 


8 



Number of Pupils Testing retarded according to Kuhlmann's revision oi 
the Binet 1911 scale. (From Kuhlman's Table VIII.) 



Nearest Life- 


Total 
Pupils 

38 


Exact 


years of retardation. 


Age 


1 or more 


2 or more 



3 or more 


6 








7 


82 


4 








8 


95 


9 








9 


91 


12 


2 





10 


84 


16 


9 


1 


11 


88 


18 


4 





12 


75 


32 


8 


1 



112 DEFICIENCY AND DELINQUENCY 

comparable with those of Goddard using the 1908 scale, 
since Kuhlmann tabulates the nearest ages instead of the 
actual ages. His age groups would therefore average 
a half year younger chronologically than Goddard's. 
Moreover, the exact amount of retardation to tenths of a 
year was then calculated from the exact age, and it is to 
be remembered that the method of calculating the mental 
age was changed in 1911 so as to start with a basal age 
in which all tests were passed. The effect of these 
changes would be that some of those recorded in Kuhl- 
mann's table as two years retarded might easily be a year 
more retarded under the same methods of calculation 
that were previously used. Using his method of compu- 
tation, it is clear that the general borderline for the im- 
mature with this scale would not be as low as we have in- 
dicated for the 1908 Binet scale. It would apparently 
be about a year less, i. e., two years of retardation for 
those six to nine years of age, and three years retardation 
for those 10 or above in order to fall within our doubtful 
group. The 13 year old group are not included here. 
They would not be even approximately random since 
those who had reached the eighth grade or above were 
not examined. It is interesting to note that the break 
in frequency of serious retardation again occurs in the 
change from those chronologically 9 years of age to those 
10 years of age. 

The Stanford Revision and Extension of the Binet- 
Simon Scale (57) has included a percentage designation of 
the degrees of ability by a classification of intelligence 
quotients (I Q's). It is interesting to find the percentage 
method of setting forth the borderlines is utilized to sup- 
plement the intelligence quotients in this important re- 
vision of the Binet-Simon Scale. It shows how the method 
may be adapted to testing of intelligence quotients. 



ADAPTING PERCENTAGE TO BINET SCALE 113 

For fixing the borderline for the immature the Stanford 
scale affords the best means provided by any of the re- 
visions or adaptations of the Binet scale. The amount of 
data on randomly selected groups of school children, by 
which these borderlines were determined, is, however, less 
than with the 1908 Binet Scale as given by Goddard 
and summarized in our Table V. The Stanford Scale 
was standardized for the immature by testing 80 to 120 
native born school children at each age from 5 to 14 in- 
clusive, a total of 905. While the 1908 scale gives cor- 
responding distributions for 114 to 222 children at each 
age from 5 to 11 inclusive, a total of 1269. Using the 
I Q's adopted by Dr. Terman for the Stanford Scale, the 
lowest 1% of the children were found to reach only an 
I Q of 70 or below, 2% to reach 73 or below, 5% to reach 
78 or below. The author designates below 70 as "definite 
feeble-mindedness, ,, 70-80 as "borderline deficiency, some- 
times classified as dullness, often as feeble-mindedness. ,, 
His "definite feeble-mindedness ,, thus includes somewhat 
fewer than our "presumably deficient' ' and "uncertain 
groups" combined. The distribution of the intelligence 
quotients was "found fairly symmetrical at each age 
from 5 to 14." The range including the middle 50% 
of the I Q's, was found practically constant (57, p. 66). 
The data for the extreme cases have not been published 
except for ages 6, 9 and 13. For these ages 1% were 75 
or below at 6 years, 2% at nine years, and 7% at 13 
(197). The results with the extreme cases at each age 
are the most important factor in fixing the borderline. 
The combined per cent, results with I Q of 905 children at 
different ages, which show 0.33% testing 65 or below and 
2.3% 75 or below, may be deceptive for separate ages. 

It seems clear that the criterion for tested deficiency 
suggested by our study is more conservative than that of 
the Stanford scale which says: 



114 DEFICIENCY AND DELINQUENCY 

"All who test below 70 I Q by the Stanford revision of 
the Binet-Simon Scale should be considered feeble- 
minded, and it is an open question whether it would not 
be justifiable to consider 75 I Q as the lower limit of ' 'nor- 
mal' ' intelligence. Certainly a large proportion falling 
between 70 and 75 can hardly be classed as other than 
feeble-minded, even according to the social criterion." 
(57, p. 81) 

In regard to the borderline for the mature with the 
Stanford scale it is especially important to note that at 
present no randomly selected mature group has been tested 
with this scale so that we are at a loss to know what would 
be a safe borderline for adults with it. It is peculiarly 
unsafe, it seems to me, to carry over an intelligence quo- 
tient which may shut out the lowest 1% of children who 
distribute normally, to the uncertain borderline of an adult 
group composed of thirty business men, 150 migrating 
unemployed, 150 adolescent delinquents and 50 high school 
students. By these data it would be impossible to tell 
what per cent, of a random group of adults would be 
shut out by this borderline of 70. 

For the Point Scale for Measuring Mental Ability, 
prepared by Yerkes, Bridges and Hardwick, we have two 
sets of data which give the only empirical basis for esti- 
mating the percentage borderlines for the various ages 
(225, 226). These data are restated in terms of percents 
in Table VII. The first part of the table shows the bor- 
derline results with the normal group composed of 829 
pupils of the Cambridge schools, 166 pupils of Iowa 
schools, 237 in the group of Cincinnati 18-year-old work- 
ing girls and an adult Massachusetts group of 50. The 
table illustrates how difficult it is to find a common border- 
line in terms of a ratio, in this case the ' 'coefficient of 
intelligence/ ' for a series of life-ages. It certainly seems 
hazardous to attempt to smooth these empirical border- 



ADAPTING PERCENTAGE TO BINET SCALE 



115 



TABLE VII.— Borderline Results with the Point Scale 

The lower range of "intelligence coefficients" for the normal group of school children 
and adults (226, Table III). 



Nearest Ages 


4-5 


6-7 


8-9 
196 


10-11 


12-13 
120 


14-15 


18-on 


No. of Cases 


84 


357 


161 


77 


284 


Presumably 
deficient 




Under 

.61 
0.4% 

.61 to 

.81 


Under 

.61 
0.6% 

.61 to 

.71 






Under 

.61 
7% 


Doubtful 


Under 
.51 


Under 
.51 


Under 
.51 

1.7% 


Under 
.61 


.61 to 
.71 


Both 


(4.8%) 


1.5% 


1.5% 


(5.0%) 


1.3% 


(6.3%) 



Pupils of Grammar School B, Cambridge, Mass. (225, Table III 



Ages 


6 


7 

73 

1.4 

14 


8 


9 
71 

2.7 
21 


10 
76 


11 


12 


13 


No. of Pupils 


71 

1.4 

11 


61 

1.5 

15 


79 
1.3 
40 


60 


52 


Per Cent of Pupils at and 
Below Points 


1.3 
35 


1.7 
33 


2.0 
38 



lines for the different ages by accepting, on the present 
evidence, the suggestion of the authors that a coefficient 
of .50 or less at any of these ages indicates the individual 
is ' 'dependent' ' and coefficients from .51-70 that he is 
* 'inferior/ ' since the data show the lowest group would 
include only the lowest 0.04% of 18 years of age and over, 
while it includes 4.8% of those in their table four and 
five years of age. Indeed, the authors note that "a few 
months' difference in age will alter the coefficient of a five 
or six year old child by ten to thirty per cent." Under 
such circumstances it would be better for the present to 
use the empirical basis suggested from the data of Table 
VII rather than to attempt to use a uniform borderline co- 
efficient for the various ages. For calculating the co- 
efficient of a particular individual, his point scale record 
should presumably be divided by the revised norms pub- 
lished by the authors, which are as follows for the nearest 
life-ages, reading the dots on their graph: 4 yrs. 15 points, 
5 yrs. 22, 6 yrs. 28, 7 yrs. 35, 8 yrs. 41, 9 yrs. 50, 10 yrs. 
58, 11 yrs. 64, 12 yrs. 70, 13 yrs. 74, 14 yrs. 79, 15 yrs. 81, 
16 yrs. 84, 17 yrs. 86, 18 yrs. 88. 



116 DEFICIENCY AND DELINQUENCY 

Since all the pupils in Grammar School B, who were not 
absent during the periods of examination, were examined, 
the distribution of these 675 pupils may be serviceable 
for obtaining a rough idea of the borderlines in terms of 
points at the different ages from 6-13 inclusive. These 
individuals "constituted the population of a city grammar 
school in a medium to poor region and including grades 
from the kindergarten to the eighth, inclusive. ,, On 
account of the small number of individuals at each age 
the errors are large and the limits should be used only 
with much caution as an indication of the general trend 
of the table. 

All the scales, it should be noted, have been tried out 
on immature groups composed only of school children. 
These would not include those children who are so de- 
ficient as not to be sent to school. The borderlines de- 
termined with school children, therefore, tend to shut 
out a slightly larger percentage of all children than of 
school children. They would, therefore, tend to class 
slightly too many as deficient. Moreover, the groups 
tested were probably in communities which are somewhat 
above the average in ability so that we should be doubly 
cautious in using the borderlines for the immature. 

(c) The change in interpreting the borderline 

FOR THE IMMATURE. 

The confusion over the amount of allowable retarda- 
tion in evaluating the results of Binet tests is illustrated 
by the variations in practise. In 1908 Binet and Simon 
said: "On the contrary, a retardation of two years is. 

rare enough; Let us admit that every 

time it occurs, the question may be raised as to whether 
the child is subnormal, and in what category he should 
be placed' ' (79, p. 269). In 1911 they had become much 



ADAPTING PERCENTAGE TO BINET SCALE 117 

more conservative. With their new scale they stated: 
"We would add that a child should not be considered 
defective in intelligence no matter how little he knows 
unless his retardation of intelligence amounts to more 
than two years' ' (78). This cautious statement seems 
to have been converted by the various translators into 
a rule that every child retarded three years was to be 
regarded deficient. Drummond, for example, in his 
translation says: "Should a child's mental age show a 
retardation of three years as compared with his chrono- 
logical age, and should there be no evident explanation of 
this, such as ill health, neglect of school attendance, etc., 
he is reckoned as deficient mentally' ' (77, p. 163). Wallin, 
however, in 1911 kept to the original conservative state- 
ment, "children retarded less than three years should 
probably not be rated as feeble-minded" (211, p. 16). 

In his book on Mentally Defective Children, before the 
1908 scale had appeared, Binet had adopted the Belgian 
practise of making a distinction between younger and 
older children as to the amounts of allowable school re- 
tardation before the question of mental deficiency should 
be raised. As a method of preliminary selection for ex- 
amination he used a retardation in school position of 
two years when the child was under 9 years of age 
and three years when he had passed his ninth birthday 
(77, p. 42). This practise was carried over into the field 
of mental tests, and Huey then qualified these limits by 
the safer allowance of four and three years of tested re- 
tardation with the change still at nine years (129). 

The German standard, formulated by Bobertag and 
accepted by Chotzen (89, p. 494), is to place the lower limit 
for the normal as less than three years retardation at ten 
years of age or less than two years retardation under that 
age. The change in the amount of retardation allowed 



118 DEFICIENCY AND DELINQUENCY 

came at the same position we advocated instead of at 9 
as was earlier suggested. 

The early practise in the United States was merely to 
regard three years retardation as the sign of feeble-mind- 
edness. This custom was even followed in 1914 for all 
under 16 years of age by Mrs. Streeter in the investiga- 
tion by the New Hampshire Children's Commission of 
Institutions in that state. She did not call any feeble- 
minded who tested over XII (40, p. 79). In both the 
1908 and 1911 editions of the Binet scale issued by Godd- 
ard, he stated that if a child "is more than three years 
backward he is mentally defective/' giving no caution 
about a borderline for the mature. This is a practise 
which has been followed so far as the immature are con- 
cerned, by Goddard's students generally. Kuhlmann 
carefully avoids the statement of a borderline with both 
his 1908 and 1911 adaptations of the Binet scale, but he 
has since advocated using an intelligence quotient of less 
than .75 with his 1911 scale to indicate feeble-mindedness 
and leaving a doubtful area from .75 to .80 (140). Stern 
suggested a borderline of .80 with the intelligence quotient 
(188). Even a quotient of .75 would call a child feeble- 
minded by Kuhlmann's 1911 scale if he tested two years 
retarded at eight and three years retarded at twelve. 
Haines suggests using, with caution, a borderline with a 
modified Point Scale which should be at 75% of the aver- 
age performance measured in points at each age for in- 
dividuals over thirteen years, and four years retardation 
for 13 years and younger (26). 

Pintner and Paterson collected in one table the test re- 
sults with the Binet scale published by thirteen different 
investigators and covering 4,429 children tested (44, p. 49). 
They do not attempt to readjust these results so as to 
allow for the very great differences in the methods by 



ADAPTING PERCENTAGE TO BINET SCALE 119 

which the different groups were chosen to be tested or 
the different uses of actual life-age and nearest life-age. 
Such a table is, as they recognize, too hazardous to use for 
determining the borderlines of deficiency. There might 
be an average difference of at least a year in the mental 
ages obtained by different investigators when no allow- 
ance is made for their different procedures. Nevertheless, 
it is interesting to note that a mental quotient of .75 is 
less conservative than the lowest 3% which is the border- 
line of feeble-mindedness that they suggest. The lowest 
3% they find would include, for example, those who were 
1.5 years or more retarded at age 5, 2.1 years retarded at 
9 and 2.8 years at age 10. 

The most important confirmation of the claim that a 
borderline for the immature should require at least 4 
years retardation comes from the Galton biometric lab- 
oratory in London. Karl Pearson has furnished a careful 
statistical treatment of Jaederholm's results in testing 
all the 301 children in special classes in Stockholm com- 
pared with 261 normal children in the same schools. 
Pearson found that the modified 1911 Binet scale which 
Jaederholm used could be corrected so that the normal 
children at each age averaged very closely to their age 
norms from 7 to 14 years of age. Under these conditions 
of the scale he generalized on the basis of the children in 
the Stockholm special classes who were from 7 to 15 years 
of age, as follows: 

'The reader may rest assured that until the mental 
age of a child is something like four years in arrear of its 
physical age it is not possible to dogmatically assert, on 
the basis of the most scientific test yet proposed as a 
measure of intelligence, that it is feeble-minded. Even 
then all we can say is that such a child would be unlikely 
to occur once in 261 normal children, or occurs under 
y 2 % in the normal child population." (167, p. 18). 



120 DEFICIENCY AND DELINQUENCY 

In a later paper he says that those children "from 4 to 
4.5 years and beyond of mental defect could not be match- 
ed at all from 27,000 children/' on the assumption of a 
normal distribution fitted to the normal Stockholm school 
children (164, p. 51). He says further: 

"It is a matter of purely practical convenience where 
the division — if there must be an arbitrary one — between 
the normal and defective child is placed; we suggest that 
it be placed at either 3 or 4 years of mental defect. But 
as meptal defect increases with the age of the mentally 
defective the division will be really a function of the 
child's age" (167, p. 37). 

Since he finds the children in the special classes fall 
further behind the normal children on the average 4 
months each year of life, this means that 3 years retarda- 
tion at 7 years of age would be equivalent to 4 years at 10. 

In spite of uncertainty introduced by the use of quo- 
tients, the general tendency in interpretation of results 
with Binet scales has thus been to make a distinction in 
the amount of retardation signifying deficiency among 
younger and older children and to require four years re- 
tardation, at least for the older ages. Our criterion for 
the borderline of three years retardation for children under 
10 years and four years for 10 years and over, with an 
extra year to be quite sure that the deficiency is sufficient 
to justify isolation, seems to be in line with the best practise 
at present among those who have had much experience 
with the Binet scale. Fortunately, little harm has been 
done to the individuals themselves by this uncertainty in 
the interpretation of the scores with the scale, since only 
questionable cases have been affected. These have gen- 
erally been diagnosed, before disposing of the child, by 
some expert who understands the sources of error in 
mental tests. On the other hand, shifting the limit of 



ADAPTING PERCENTAGE TO BINET SCALE 121 

allowable retardation by one year makes a great differ- 
ence in the estimation of the frequency of feeble-minded- 
ness in particular groups, as will be shown in our discussion 
of deficient delinquents. 



CHAPTER VI. DELINQUENTS TESTING 
DEFICIENT 

A. At the Glex Lake Farm School for Boys, 
Hennepin County, Minnesota. 

We are now in a position to evaluate the Binet examin- 
ations of delinquents. Let us first note our results for 
a group of 123 consecutive cases at the Hennepin County 
Detention Home.* It is not a detention home in the 
sense of a place where children are held awaiting the dis- 
position of their cases by the Juvenile Court. It is better 
described by its unofficial title, The Glen Lake Farm School 
for Boys. This county training school for delinquents is 
located on a splendid farm beside a small lake fourteen 
miles outside of Minneapolis. The boys are sent there 
by the juvenile court for a few months' training as an 
intermediate discipline between probation and sentence 
to the State School at Redwing. 

The character of this group of 123 randomly selected 
delinquents is further indicated by the fact that 69 of 
them had already been brought into court two or more 
times, 54 were first offenders. Boys are sent to Glen 
Lake whenever the nature of their delinquency or the 
conditions at home,, together with the personality of the 
boy, seem to the court to require this special training. A 
summary of the offenses for which the boys were brought 
into court does not, therefore, show the character of the 
boy as it is known to the court through the evidence and 



*During the months when these examinations were made we failed 
to test six boys, four of whom were sent to relatives outside of the state. 
One other could not be tested because of his unfamiliarity with the 
English language. 

(122; 



DELINQUENTS TESTING DEFICIENT 123 

the efficient service of the probation officers. It shows, 
however, that the last offenses for which this group were 
being disciplined were as follows: Petit larceny 29, tru- 
ancy 25, incorrigibility 25, burglary 9, grand larceny 6, 
disorderly conduct 4, malicious destruction of property 4, 
trespass 3, sweeping grain cars 3, breaking and entering 
3, indecent conduct 2, miscellaneous offenses one each 8, 
total 123. Perhaps a more important indication of the 
character of the offenders in this group is that they repre- 
sent about a quarter of the cases brought before the juv- 
enile court during the period of this study, a little over a 
year. With the exception of a very few cases sent di- 
rectly to the State Industrial School they may thus be 
regarded as typically the worst quarter of the delinquent 
boys under 17 years of age in Minneapolis. 

The majority of boys were tested by myself after several 
year's experience with the clinic in mental development 
at the University of Minnesota and after examining many 
other delinquents. Some were tested by assistants from 
the university clinic, Mrs. Marie C. Nehls and Mr. Har- 
old D. Kitson, who had been specially trained for this. 
Their detailed reports were carefully gone over and evalu- 
ated. The Binet 1908 series (136) was used, except that for 
tests above XII either tests XIII were used, or later 
these were supplemented by two other tests, which have 
been placed in the age XV group or adult groups, in the 
revisions of the Binet scale published by Goddard (110) 
or Kuhlmann (135). This variation was of small import- 
ance since a boy was regarded as of passable intellect if 
he scored X.8. We always gave the three tests of the 
XIII group and the boy was credited with age XIII if 
he passed two out of the original XIII year tests or four 
out of five tests given above XII. In accordance with our 
conservative position the rule of this 1908 scale for scor- 



124 



DEFICENCY AND DELINQUENCY 



ing was followed and the boy credited with the highest 
age for which he passed all but one test, plus one year for 
each five higher tests passed. This is the basis of the 
1908 form of the scale as standardized by Goddard. 
Appendix II gives the detailed results for each boy with 
exact life-age and tenths of test-age on the scale, basal 
test-age with the tests, grade in school at the first of Sep- 
tember when he was of this life-age and offense for which 
he was being disciplined. It also indicates which boys 
were repeaters. The results of this table are summarized 
in Tables VIII and IX. The life-ages at the last birth- 



TABLE VIII. 
Test-Ages of the Glen Lake Group of Delinquent Boys 



Test- 


Life- Ages at Last Birthday 


Ages 


6 


7 
1 


8 


9 


10 


11 


12 


13 


14 


15 


16 


Totals 


VII 


1 


VIII 


1 








1 






1 








3 


IX 








4 


2 


1 




1 






1 


8 


X 








1 


2 


2 


1 


5 


2 


3 


1 


17 


XI 








1 


2 


8 


6 


9 


6 


13 


3 


48 


XII 










1 


2 


5 


4 


6 


7 


3 


27 


XIII 
















1 


4 


8 


5 


18 


Total 


1 


1 





6 


8 


13 


12 


21 


18 


30 


13 


123 



day are used rather than the nearest ages, since this ac- 
cords with Goddard's standardization and with the com- 
mon use of the term "age." Moreover it seems to con- 
form to the best practise and to be less likely to lead to 
mistakes. Table IX also shows the school position of 
each boy. Since a number of the older boys had left 
school, in order to tabulate their school positions in refer- 
ence to their life-ages it was necessary to assume that they 
would have continued to progress normally from the pos- 
ition they held when they left. The Minnesota law re- 
quires attendance at school until sixteen years of age 



DELINQUENTS TESTING DEFICIENT 



125 



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126 DEFICIENCY AND DELINQUENCY 

unless before that the child graduates from the eighth 
grade. In this group most of those sixteen years of age 
and a goodly number of those fifteen years old had left 
school, so that their school position had to be advanced a 
year in the table; a very few of the 16-year-olds had to be 
advanced two years in the table. In all cases the school 
position is given relative to the first of September when 
the boy was of the life-age given. Either ages six or 
seven are taken as satisfactory for the first grade, ages 
seven or eight for the second grade, and so on with the 
other grades. 

The summary of the Binet scale testing of this group 
according to the valuation which we have adopted, shows 
two clear cases of tested deficiency. One boy who was 
13 years of age tested VIII and was the only case sent to 
the State School for Feeble-Minded from this group. 
The other was 16 years of age and tested IX. Besides 
the two presumable deficients, seven other boys were 
uncertain according to our interpretation, as judged by 
the Binet tests alone. One of them was 13 and tested 
IX, the others were 14, 15 and 16 and tested X. This 
would make a total of 7% possibly socially deficient, since 
they were all delinquent. This seems to be the largest 
estimation of deficiency which would be justified on the 
basis of these test results. To show, however, how im- 
portant is the interpretation of the results obtained with 
Binet examinations when treated in gross, it need only 
be stated that a few years ago, when this study began, it 
was not uncommon to count all who were retarded three 
or more years and testing XII or under as feeble-minded. 
On that absurd basis, there would be 45 such cases (37%). 
As we have considered at length the reasons for not 
counting a person as even of doubtful intellect who tests 
XI or above or is less than three or four years retarded, 
we do not need to rehearse them here. 



DELINQUENTS TESTING DEFICIENT 127 

B. Comparison of Tested Deficiency Among 
Typical Groups of Delinquents. 

Using our conservative basis for interpreting the re- 
sults of Binet examinations, let us now review the evidence 
of the proportion of delinquents which is intellectually 
deficient. We shall compare the available data on groups 
of tested delinquents which have not been subjectively 
selected, provided that the data permit of restatement on 
the basis of the borderlines we have adopted. The evi- 
dence of tested deficiency on over 9000 objectively select- 
ed delinquents has thus been assembled under approxi- 
mately the same interpretation of the borderlines. This 
should help to make it clear how extensive the prepara- 
tions must be for dealing with this problem of the defective 
delinquent and where the needs are most pressing. It 
should also enable us to discover when the estimates have 
been excessive. We shall* confine ourselves to the re- 
ports of objective test examinations, so that the estimates 
do not depend upon the judgment of the examiner alone. 
A bibliography of these studies is given at the close of 
the book. How much more has been accomplished in 
this field in the United States than abroad is illustrated 
by the fact that repeated search has failed to discover 
any reports of Binet examinations on representative, 
randomly selected groups of delinquents in any foreign 
country. Binet examinations have been made of juvenile 
delinquents in Breslau (34) and in Frankfurt a. M., and 
in London (56) ; but only upon selected cases. 

Those who wish to compare the results as to tested de- 
ficiency with the subjective opinions of various estimators 
should consult the reviews of this literature by Bronner 
(6) and by Gruhle (121). The effect of such a comparison 
is an increasing conviction that it affords dubious evi- 



128 DEFICIENCY AND DELINQUENCY 

dence of the relative amount. of deficiency in different 
groups of delinquents. Without objective tests, there 
is no means of telling what amount of mental retardation 
the different experts would class as feeble-mindedness. 

(a) WOMEN AND GIRL DELINQUENTS IN STATE 
INSTITUTIONS. 

Women in state penitentiaries are a small group among 
delinquents in institutions. According to one study by 
Louise E. Ordahl and George Ordahl* the frequency of 
tested deficiency is smaller among them than among wo- 
men committed to reformatories, who in general commit 
less serious crimes. All except one of the 50 women pris- 
oners enrolled were tested with the Kuhlmann 1911 re- 
vision of the Binet scale. About half were negro women. 
Only 6 (4 negroes) tested IX or below and were in our 
group of presumably deficient by the tests. Twenty 
others (13 negroes) tested one Binet age higher and were 
in the doubtful group. 

If we consider the worst condition so far as intellectu- 
al deficiency is concerned, we find it in the reformatories 
and training schools for women. Dr. Weidensall applied 
the 1908 Binet scale to 200 consecutive women, 16 years to 
30 years of age, as they were admitted to the New York 
Reformatory for Women at Bedford. Seventy-seven 
tested IX or under and were within our presumably de- 
ficient group. An additional 74 tested X and were in 
the uncertain group, although if we regard them all as 
deficient because of their persistent delinquency, we have 
a total of 75% (59). These results were duplicated by 
Dr. Fernald (16). She tested 100 other consecutive 
cases with the 1911 scale and found 41% tested below 
X, our presumably deficient group. She regards these as 
' 'feeble-minded with certainty/ ' 

*Louise Ordahl and George Ordahl. A Study of 49 Female Con- 
victs. Journal of Delinquency, 1917, 2, 331-351. 



DELINQUENTS TESTING DEFICIENT 129 

Dr. Katherine Bement Davis, the former superintend- 
ent at Bedford, estimated herself that among 647 prosti- 
tutes who were inmates there, 107 were ' 'feeble-minded 
(distinctly so);" 26 "border-line neurotic;" 26 "weak- 
willed, no moral sense;" 11 "wild, truant, run-a-ways." 
This makes a total of 26% of this group whom she ap- 
parently thought might possibly be classed feeble-minded 
or of questionable mentality because of deficient intellect 
or will {11). It is quite clear that the objective tests 
give a much better basis for comparison of the Bedford 
group with those which are to follow. 

The professional prostitute confined in institutions for 
delinquents has been carefully studied and tested by the 
Massachusetts Commission for the Investigation of the 
White Slave Traffic, So Called {36). Three groups of 100 
each were examined "without selection, except that all 
had a history of promiscuous sex intercourse for pecun- 
iary gain." One of the groups consisted of young girls 
under sentence in the State Industrial School for Girls, 
the House of Refuge and the Welcome House. A second 
group consisted of those just arrested and awaiting trial 
in the Suffolk House of Detention in Boston. The third 
was made up of women serving sentence in the State 
Reformatory for Women, the Suffolk County Jail and the 
Suffolk House of Correction. "These three groups re- 
present the young girls who have just begun prostitution, 
the women plying their trade on the streets at the present 
time, and the women who are old offenders." 

The Binet tests were applied to 289 of the 300 women 
examined, and other psychological tests were applied in 
doubtful cases. The ages ranged from 12 up. Only 
10 were under 15 and 32 were 36 years of age or over. 
The investigators classed no; case as feeble-minded which 
did not test XI or under, but they did not class as feeble- 



130 DEFICIENCY AND DELINQUENCY 

minded 107 other cases which tested XI and under. The 
Commission's diagnosis is therefore conservative. It re- 
garded 154 cases (51%) as feeble-minded, 46 in the de- 
tention house group and 54 in each of the others. If we 
ask how many tested below our standard we can not tell 
exactly, since the report does not state whether X.8 was 
classed as X or XI. It shows 81 tested IX or under 
(27%) and these were nearly all, therefore, within the 
limits of our group presumably deficient. Ninety-nine 
others tested X, a total of 60% testing below our border- 
line for presumable and doubtful deficients. Since only 
2 cases were under 14 years of age, these figures could not 
be much disturbed by the younger girls. We can be 
reasonably sure, then, that at least 27% of these prostitutes 
should be placed under permanent custodial care, and 
probably 50% would be more nearly correct. 

In a recent report of the Bureau of Analysis and In- 
vestigation of the New York State Board of Charities* 
Dr. Jesse L. Herrick reports testing 194 inmates of the 
state reformatory for women known as the Western 
House of Refuge. The Stanford Scale was used, 25% 
tested IX or under with that scale and 14% tested X. 
In the same bulletin the report is made of Binet ages for 
607 inmates of the New York Training School for Girls. 
Four versions of the scale were used so that the estimates 
are somewhat affected. Moreover, 97 girls were under 
15 years of age. The table of Binet ages indicates 20% 
testing IX or under and 28% testing X. 

Hill and Goddard (30) report examining a group of 56 
girls who had been in a reformatory and were under pro- 
bation with a certain officer. In this entire group they 
found only four who were not feeble-minded, "as we usual- 
ly define feeble-mindedness." Presumably this means 

♦Eugenics and Social Welfare Bulletin No. XI, 1917, p. 73. 



DELINQUENTS TESTING DEFICIENT 131 

three or more years retarded, including those who tested 
XII, so that it cannot be regarded as a conservative esti- 
mate. No further data is provided for interpreting the 
borderline. 

Taking up the younger and milder girl delinquents, 
Dr. Haines reports the examination of an unselected 
group of 329 at the State Girls Industrial Home near Dela- 
ware, Ohio (26). They were all under 21 years of age 
and represent less hardened delinquents than the older 
groups at the reformatories for women. The Ohio group 
was tested with the Binet 1911 scale as well as with the 
Yerkes-Bridges Point Scale. Counting a result of .8 of 
a year as placing the case under the next mental age above, 
as we have in fixing the limits, we find that his results are 
given with such excellent detail that we may fairly com- 
pare the percentages with our standard for the Binet 
Scale. On this basis 70 of these delinquent girls (21%) 
are clearly deficient and 55 more are in the uncertain 
group, a total of 38%. 

As a check upon results, we may compare the report of 
Miss Renz for 100 consecutive admissions to the same in- 
stitution in 1912, tested with the Binet scale (47). She 
found 29 tested IX or under, 49 tested X or under, 
slightly more than was shown by the Haines tests. Miss 
Renz' report, however, does not show how many of the 
girls were under 14 years of age and might thus be ex- 
cluded from the deficient groups. 

In the California School for Girls, Grace M. Fernald* 
examined 124 cases as they entered the school. Twenty- 
four tested under XI with both the Binet 1911 and Stan- 
ford revision. This is a further indication of the less fre- 
quency of feeble-mindedness in the state schools for girls 
than in the reformatories for women. 

*Grace M. Fernald. Report of the Psychological Work at the Cal- 
ifornia School for Girls. J. of Delinquency, 1916, i, 22-32. 



132 DEFICIENCY AND DELINQUENCY 

Dr. H. W. Crane reports the results of the Binet test- 
ing at Adrian, the Michigan Industrial School for Girls, 
which receives only minors and corresponds to the Ohio 
Industrial Home {37). The Binet 1911 scale was used, 
but this grouping in mental ages may mean that a few 
more cases are thus classed deficient than with our stand- 
ardized borderlines which place the subject in the higher 
age group when he scores .8. It is to be remembered 
also that the borderlines for those whose life-ages are 
under 15 have not been as well standardized with the 
1911 scale. The testing was done under the direction of 
a state commission appointed to investigate the extent of 
mental defectiveness (37). Dr. Crane was assisted by 
three other workers. The results at Adrian show, among 
the 386 inmates, 131 or 34% tested in our groups of pre- 
sumably or uncertain intellectual deficients. Seventy- 
seven of these, in our uncertain group, should only class 
as deficient because also delinquent. The investigators 
give it as their opinion that 16.7% of the inmates were 
feeble-minded but not reached by the tests. 

The entire population of the Illinois State Training 
School for Girls at Geneva was tested by Louise E. and 
George Ordahl.* The Kuhlmann revision of the Binet 
Scale, supplemented by the Stanford Scale, for the older 
ages, was used. Among the 432 tested 13 per cent, tested 
below our borderline for the presumably deficient and 22 
per cent, more in the doubtful group. 

Dr. Otis, resident psychologist at the New Jersey State 
Home for Girls at Trenton, examined 172 girls between 10 
and 20 years of age inclusive (43). Since she said it was 
"a preliminary testing' ' and "not many of the smaller 
girls were included/ ' we conclude that it was a somewhat 

*Ordahl, Louise E. and George. A Study of Delinquent and De- 
pendent Girls. J. of Delinquency, 1918, III, 41-73. 



DELINQUENTS TESTING DEFICIENT 133 

selected group. She regarded those who stand between 
eleven and twelve as practically normal and those who 
stand below ten as without doubt defective. She then 
publishes three groups: "Defectives," 45% (77 cases) 
high grade; "Morons," 30% (52 cases); and "Presumably 
Normal," 25% (43 cases). Since she does not give the 
distribution of the cases it is not possible to tell how many 
of her group were less than four years retarded. Her 
statement of the ages, however, shows that not more than 
7 of the defectives could have been less than four years 
retarded and not more than 12 of the combined group 
of defectives and morons tested X or over. We may be 
sure, therefore, that at least 68% of these girls are of ques- 
tionable intellectual ability according to the conservative 
standard adopted in this discussion. 

Dr. Bridgman has reported the examination of 118 
girls, 10 to 21 years of age, successively admitted to the 
State Training School for Girls at Geneva, 111. She 
states that 89% (105 cases) "showed a retardation of 
three years or more." The distribution of cases is not 
given so that it is not possible to tell how many testing 
X, XI, and XII were classed as feeble-minded or how 
many tested only three years retarded. The published 
estimate is undoubtedly extreme, but I have no means of 
making a more conservative estimate on this group. It 
is interesting, however, to note that only 14 of the cases 
were not sexually immoral. These were all cases which 
were either dependent or sent because uncontrollable at 
home and all tested as passable intellectually. She 
states that "according to the Binet tests, 97% of the chil- 
dren (5) sent to this institution because of sexual im- 
morality are feeble-minded as well." This percentage 
also would be decidedly discounted on a conservative test 
standard. In another place Dr. Bridgman makes the 



134 DEFICIENCY AND DELINQUENCY 

important statement that of 400 girls admitted to Geneva 
60% were suffering from venereal disease (4). 

Mr. Bluemel (2) found that 24 out of 50 girls sent from 
Judge Lindsay's Juvenile Court in Denver to the State 
Industrial School or the Florence Crittenden Home tested 
XI or under and four or more years retarded. This is 
less conservative than our standard, which would exclude 
those who tested XI as above even the uncertain group 
in intellect. 

Dr. Pyle (46) has tested the 240 girls at the Missouri 
State Industrial Home for Girls with his standardized 
group tests. These girls are from 7 to 21 years of age 
and his table gives the results with each of six tests. The 
most significant fact for our purpose is that with the dif- 
ferent tests from 50 to 88 per cent, fall below the averages 
of normal individuals who are three years younger. He 
says, "Our figures would indicate that about one- third of 
these delinquent girls are normal and about two-thirds 
subnormal. Most of them are probably high grade 
morons/ ' This is based apparently on 69% being the 
average of the results of six different tests as to the per- 
centages three years or more retarded from their life ages. 
He indicates, however, that 38%, similarly calculated, 
are within the average deviation of the normal groups for 
their life-ages. This indicates that the lowest 62% test 
only as low as we should expect to find the lowest 21% of 
random groups of corresponding ages. They should 
certainly not be regarded as testing feeble-minded. 

(b) WOMEN AND GIRL DELINQUENTS IN COUNTY 
AND CITY INSTITUTIONS. 

When we turn to those who are cared for locally in city 
or county institutions, we find Sullivan (56) has exam- 
ined 104 women and girls held temporarily at the Hollo- 



DELINQUENTS TESTING DEFICIENT 135 

way jail in London, most of whom were between 16 and 
25 years of age. Apparently the cases were especially 
selected for examination and therefore do not represent 
the general condition there. He was interested, how- 
ever, in finding the relative amount of deficiency among 
different classes of these inmates and he gives the de- 
tailed results with the Binet 1908 scale on small groups 
of these different types which we may classify by our 
standard as follows: 

Twenty non-criminal, either not guilty or guilty of 
unimportant offenses, who represent, he thinks, the or- 
dinary conditions among the corresponding working class 
in this community, 3 presumably deficient, 5 uncertain; 
twenty criminal by reason of the occasion, 1 presumably 
deficient, 6 uncertain; twelve impulsive criminals, 1 
presumably deficient, 2 uncertain; eight moral imbeciles, 
2 presumably deficient, 2 uncertain; twenty- four reci- 
divists, 2 presumably deficient, 8 uncertain; twenty 
prostitutes, 3 presumably deficient, 8 uncertain. To- 
gether these different types of women in jail form a mot- 
ley group of 104 of whom 12 test presumably deficient, 
31 uncertain, a total of 41%. 

Ordinary prostitutes are about as frequently deficient 
as are those in reformatory institutions, if we may judge 
by an important study of women who were sex offenders 
but not in institutions for delinquents. The report is 
by Dr. Clinton P. McCord, health director of the Board 
of Education at Albany (35). One group consisted of 
fifty cases of sex offenders who were not legally delin- 
quents at the time but were living in houses of ill-fame. 
Their ages ranged from 22 to 41 with an average age of 27. 
Nine of these (18%) tested IX or under with the Binet 
1911 and 18 tested X, a total of 54% presumably and 
doubtfully deficient. Another 38 cases were staying at 
a House of Shelter where most of them had been sent by 



136 DEFICIENCY AND DELINQUENCY 

the courts. Nineteen of these tested IX or under (50%), 
while 13 more tested X, a total of 84%. Since their ages 
ranged from 12 to 40 years with an average of 18 we 
cannot tell how many might be above the borderline on 
account of an age less than 15 years, but probably very 
few. A third group consisted of 9 street walkers and 3 
wayward girls. Among these 7 tested presumably or 
doubtfully deficient. 

The McCord study of prostitutes not legally delin- 
quent at the time of examination is confirmed by the Vir- 
ginia State Board of Charities and Corrections in a special 
report to the General Assembly which gives the results 
of examining the prostitutes in an entire segregated dis- 
trict in one of the Virginia cities (58). Its table shows 
that, among 120 of these women, 43, or 36%, tested ap- 
proximately under our borderline for the presumably 
deficient, while 67 cases, or 56%, tested below approxi- 
mately our borderline for the presumably passable in- 
tellects. 

These results are similar to Weidensall's* findings 
among the unselected group of unmarried mothers in the 
Cincinnati General Hospital. While she does not give 
the number tested with the Yerkes-Bridges scale, she 
indicates that 48% tested as low-grade morons or worse, 
which should correspond to a test age of IX or lower. 
Twenty-two per cent, had intelligence coefficients of .50 
or less and 32%, from .51 to .70. A Study of Fifty Feeble- 
Minded Prostitutes^ by Mary E. Paddon gives, an admir- 
able summary of the social history of prostitutes who 
tested deficient. 



*Jean Weidensall. The Mentality of the Unmarried Mother. Na- 
tional Conference of Social Work, 1917. 

tJ. of Deficiency, 1918, III, 1-11. 



DELINQUENTS TESTING DEFICIENT 137 

Dr. Bronner has made a careful study with Binet tests 
of a younger group of randomly selected girls at the Cook 
County Detention Home which is connected with the 
juvenile court at Chicago. The group included 133 girls 
10-17 years of age inclusive, who were held awaiting a 
hearing or were temporarily cared for in the detention 
home. The Binet tests were given to all who did not 
show clearly that they were of passable mentality by com- 
pleting the sixth grade or above without retardation, and 
passing school tests in long division and writing from 
dictation. A 14-year-old child "passing all the 10-year- 
old tests and some, but not all, of the 12-year tests," was 
regarded as doubtful. She was not classed as feeble- 
minded without further testing and study. Dr. Bronner 
does not state her criterion for the borderline with the 
younger children, but we may judge that her borderline 
was more likely than ours to have classed a child in the 
presumably deficient group. Her summary shows only 
15 girls "probably feeble-minded' ' (11.2%), and 2 others 
"possibly" so. From her description we may suppose 
that the "probable" group were comparable with our 
test standard of presumably deficient, plus perhaps a 
few conative cases. 

Mention should also be made of the work of Dr. Bron- 
ner to which we referred under the earnings of the mental- 
ly retarded (6). This group^of 30 randomly selected de- 
linquent women at a local detention home in New York 
tested, with two or three possible exceptions, no lower 
than a similar group of women servants who had never 
been offenders. Her data do not enable us to determine 
how many would fall below our borderlines. 

Stenquist, Thorndike, and Trabue (54) report the re- 
sults with the Binet 1911 tests, under a slightly modified 
procedure, for 75 randomly selected dependent and 4 



138 DEFICIENCY AND DELINQUENCY 

delinquent girls cared for by a certain county, excluding 
those children within the county sent to an institution for 
the feeble-minded. The children were from 9 to 16 years 
of age, with a medium age of 11 years. The line between 
the delinquent and dependent groups with these younger 
children becomes rather obscure. They state: "A child 
may, in the county in question, become a public charge by 
commitment by an officer of the poor-law on grounds of 
destitution, or by an officer of the courts on grounds of 

delinquency The decisive factor is often 

simply whether the. parents are more successful in getting 
justices to commit their children than in getting poor- 
law officers to do so." With the detailed records which 
they give it is possible to apply our standard even for the 
immature, although it is certainly less adequate for those 
under 15 years of age tested by the 1911 scale. I have 
translated their corrected Binet ages back to the original 
test ages, since their summary of retardation in terms of 
years below average ability at each age is not comparable 
with our borderline. Among the 79 girls who are mostly 
dependent, there are 5 girls, or, 6%, who fall within our 
presumably deficient group and 8 in the doubtful group, a 
total of 16%. So far as serious deficiency is concerned 
the situation is undoubtly worse among delinquents than 
among corresponding groups of dependents. The figures 
of these investigators show this for their group of boys, 
to which we shall refer later. 

Certain other groups of women and girls have been 
examined with the Binet or other tests, but the results are 
of little significance for judging the problem of deficiency 
objectively, since the individuals were either selected for 
examination because they were thought to be abnormal 
mentally or because there are not adequate norms for 
determining the borderlines with the particular tests used. 



DELINQUENTS TESTING DEFICIENT 139 

At the New York State Training School for Girls in Hud- 
son, we find that 208 selected cases who were not profiting 
by their training were examined with the 1911 scale. 
They ranged in life-age from 12 to 20. We cannot de- 
termine how many were under 14 years of age, or how much 
effect might have been produced by selecting dull cases; 
but 44 tested IX or under and 52 tested X (158). Dr. 
Spaulding (183) used Binet and other psychological tests 
on a group of 400 inmates of the Massachusetts Reforma- 
tory for Women at South Framingham; but she gives 
only her judgment based on the examination and history 
of the cases so that we have no data on this group for 
comparison. Her statement that 16.8% showed ' 'marked 
mental defect, i. e., the moron group" and 26.8% showed 
' 'mental subnormality (slight mental defect)" is an ex- 
cellent illustration of the best type of subjective judg- 
ment on consecutive cases, since she is familiar with test 
results. For her purpose of deciding how to care for the 
women it is of undoubted value, but for comparative 
purposes it is clear that it is impossible to tell how her 
subjective opinion would agree with that of an equally 
competent diagnostician, or what is meant by her terms 
' 'feeble-minded" or "subnormal." For scientific purposes 
the Binet results for her group would be of much value, for 
we should like to know whether the conditions at Bedford 
are typical among the women's reformatories for the older 
offenders. 

Dr. Rowland used psychological tests other than the 
Binet scale with a group of 35 at the Bedford Reformatory 
for Women, but there are no adequate norms for the com- 
parison of her results with the general conditions (49). 
Baldwin (1) has shown that delinquent colored girls, 13 
to 21 years of age, in the girls' division of the Pennsylvania 
Reformatory school at Sleighton Farm are inferior to white 



140 DEFICIENCY AND DELINQUENCY 

girls in the same institution in a learning test. As "cited 
by Gruhle, {121) Cramer (10) used an Ebbinghaus com- 
pletion test, definition tests, etc. with 376 delinquent girls 
in Hanover, but there are no borderlines for comparison. 
As cited by Bronner, von Grabe gave several psychological 
tests to 62 prostitutes treated in the city hospital in Ham- 
burg and compared them with a control group of 30 (6). 

The most striking conclusion that comes out of the 
study of this evidence of frequent deficiency among de- 
linquent girls and women is the close association between 
sex offenses and deficiency. One hundred and four out 
of 118 consecutive admissions at the Illinois training 
school were known to be sexually immoral. At Bedford 
94 out of 100 consecutive cases had records of immorality, 
while three-fourths of the same group tested questionable 
in intellect by our standards (11). This evidence, taken 
with the report of the Massachusetts' Commission and 
the tests of sex offenders who were not at the time legally 
delinquents, reported by McCord, and the Virginia Com- 
mission, leaves little doubt that there is an excess of de- 
ficiency among this type of offender. Many of these de- 
ficient girls probably at first drift into the life of prosti- 
tution. They are passive rather than active agents. 
This distinction in the nature of the offense accounts for 
some of the difference between the sexes in this form of 
delinquency. Furthermore our public attitude in matters 
of social hygiene has made the isolation of the female 
sex more common. Part of this may be due to the great- 
er difficulty of proof in the case of men and boys, but in 
part it undoubtedly means that men have not been held 
to as high a moral standard as women in this regard. The 
greater frequency of deficient sex offenders among girls, 
does not mean that girls are more likely than boys to be 
active sex offenders. They are, however, more likely to 



DELINQUENTS TESTING DEFICIENT 141 

be isolated for such offenses, and also more likely to be 
passive offenders. 

The greater amount of deficiency found among female 
delinquents than among corresponding groups of males is 
thus easily accounted for by frequent association between 
deficiency and sex delinquency on the part of girls and 
women. The combination of legal sex delinquency and 
deficiency is due both to a native sex difference and a dif- 
ference in social attitude toward the two sexes as to this 
form of offense. Whichever may be the main cause of 
the facts found, it is clear that deficiency is, today, most 
serious among female offenders. It is so serious that 
some of our reformatories for women might even prove to 
be practically institutions for deficient delinquents. 
It is in this type of institution without doubt, that the 
immediate problem of the deficient delinquent is most 
pressing. Permanent guardianship, if not isolation, for at 
least a third of the inmates of an institution like Bedford 
which shows this amount of clear tested deficiency, under 
our very conservative standard, would seem to be a wise 
move in social hygiene. It should be undertaken at once 
with vigor. A more fundamental change in our social 
attack of this problem means state guardianship before 
adolescence for all girls testing presumably deficient under 
our standard, when their deficiency is not due to remov- 
able handicaps. 

(C). MEN AND BOY DELINQUENTS IN STATE INSTITUTIONS. 

For the purpose of judging the importance of the ques- 
tion of feeble-mindedness among the most serious crim- 
inals, those committed to the state prison, we have a very 
important study by Rossy (48). Three hundred cases 
were taken at random with the exception of a few selected 
cases on which a report was requested. In this group, 



142 DEFICIENCY AND DELINQUENCY 

thirty prisoners could not be examined either because of 
language difficulties or because of their refusal to be tested. 
The Point Scale of Yerkes and Bridges was used and the 
results are presented in terms of mental ages on that scale. 
The examiner considered all those testing XI or under 
as feeble-minded and found 22% of the 300 in this class. 
This is less conservative than even our doubtful standard, 
but I estimate that 16% would fall within our doubtful 
and presumably deficient groups. This includes 11% 
who test X or under with the Point Scale plus 54% of those 
who tested XI. This estimate is made on the basis of 
the tables given by Haines (26), comparing Binet 1911 
results with those of the Point Scale on the same individ- 
uals. It adds the proportion of those testing XI with 
Point Scale, who would test nearer X with the Binet 1911 
scale. 

Ordahl* examined 51 convicts in the penitentiary at 
Joliet, 111. They "were selected in a manner thought to 
secure fair representation of the prison population as a 
whole." The Kuhlmann 1911 Binet scale was used and 
supplemented by tests for 13 to 18 years taken from the 
Stanford scale. It is possible that selection affected the 
results with this small group, since 25% showed test ages 
of IX or under and 36% tested X or under. 

Haines tested with the Point Scale 87 consecutive ad- 
missions to the Ohio penitentiary (24). He found 18% 
tested below a record corresponding to X.6 on the Goddard 
1911 scale, which is about the upper limit of our doubtful 
group. 

That a smaller proportion of the state prison inmates 
is found intellectually deficient than is found among 
the inmates of the industrial schools is not surprising. 

*George Ordahl. A Study of Fifty-Three Male Convicts. J. of 
Delinquency, 1916, 1, 1-21. 



DELINQUENTS TESTING DEFICIENT 143 

This may be due to various causes. Among these may 
be mentioned the failure to recognize feeble-mindedness, 
heretofore, among the younger delinquents while the 
adult feeble-minded were more carefully isolated in their 
proper institutions. The deficient adults have also been 
reduced in frequency by the excessive mortality. Prob- 
ably the feeble-minded are not so likely to plan or commit 
felony as lesser crimes and misdemeanors. Moreover 
the adult feeble-minded may be more stable and less in- 
clined to delinquency than adolescents. Whatever may 
be the explanation, deficiency generally does not seem to 
be as common among the inmates of a state prison as 
among minor delinquents in states which are in the fore- 
front in the care of their feeble-minded. 

The state reformatories reach a class of delinquents 
between those of the state prisons and the state industrial 
schools. In Minnesota all the inmates of the reformatory 
except 80, who were disqualified by inability to speak 
English or otherwise, were tested by Dr. E. F. Green. 
Men are sent there only between the ages of 16 and 30, so 
that his table of mental and life-ages gives us the oppor- 
tunity to apply our criteria accurately. Thirteen per 
cent, of the 370 examined tested IX or under and were pre- 
sumably deficient, while 22% more were in the uncertain 
group testing X (22). 

In a report of the Binet results with 996 inmates of the 
Iowa Reformatory, which Warden C. C. McClaughry 
kindly sent me, 200 tested IX or under and 146 tested X, 
a total of 35% including the doubtful group. The range 
of ages was from 16 to 49. The Warden notes that the 
tests were not made by an experienced psychologist. 
"In many cases it is suspected that the crafty criminal 
was endeavoring to lower his standing as to mentality 
in the hope of excusing or mitigating his crime in the eyes 



144 DEFICIENCY AND DELINQUENCY 

of the Board of Parole/ ' The results, however, agree 
well with what has been found in similar institutions. 

Supt. Frank Moore of the New Jersey Reformatory at 
Rahway says, "Nearly every young man who has entered 
our institution in the last eighteen months has been tested 
by this system (Binet), and the results have shown that 
at least 46 per cent, were mentally subnormal" (38). By 
his discussion this seems to mean that they tested below 
XII which would mean that all those testing XI were less 
deficient than our standard for doubtful cases. These 
young men were from 16-25 years of age and 17.5% of 
them had had one year or less in school. Ten per cent 
could not be examined because of unfamiliarity with 
English. A later report in 1912 regarding the same in- 
stitution (42) says that 600 of the inmates have been 
examined with the Binet tests in two years, but does not 
state how these were selected. Of those examined we 
are told "48% are of the moron type of mental defectives, 
ranging in mentality from three to eight years, below the 
average normal adult." Again, no further information is 
given so that it is impossible to allow for those testing X 
or XI or for the cases only three years retarded. Both 
of these estimates at the New Jersey Reformatory are 
excessive when judged by conservative borderlines. 

Dr. Fernald has applied 11 objective tests to a represent- 
ative group of 100 inmates at the Massachusetts Re- 
formatory (15) but the norms for the tests which he used 
were obtained, for the most part, by testing a dozen boys 
so that the line which he draws for the limit of the defectives 
is largely a matter of his expert opinion and the estima- 
tion loses objective character. He estimates that 26% 
of his group whose ages run from 15 to 35 inclusive were 
defective. Beanblossom* has published an account of 

*M. L. Beanblossom. Mental Examination of Two Thousand De- 
linquent Boys and Young Men. Indiana Reformatory Print, 1916, 
p. 23. 



DELINQUENTS TESTING DEFICIENT 145 

tests on 2000 inmates of the Indiana Reformatory. Some 
of the Binet tests as well as other tests were used but the 
published results do not admit of reinterpretation. 

Comparing the reports from the Minnesota, Iowa, and 
New Jersey reformatories with the tested deficiency found 
in institutions for women delinquents on the basis of the 
same borderline with the scale, the records indicate clearly 
that the percentage of feeble-mindedness is greater in 
the reformatories for women. At the Bedford Reforma- 
tory for women, for example, Dr. Wiedensall's results 
show that the corresponding borderline to that used in 
the New Jersey men's reformatory which reported 46% 
deficient, would class 100% at Bedford as feeble-minded, 
where only one case in 200 tested as high as XII. A con- 
servative estimate of tested deficiency in men's reforma- 
tories from the above data would be from 15 to 20%. 

In the state institutions for minor delinquents, usually 
called industrial schools, we have several studies of rep- 
resentative groups with sufficient data to make ob- 
jective interpretations comparable with our standard. 
In Ohio, Dr. Haines (26) reports on the examination of 
671 delinquent boys 10 to 19 years of age at the Boys' 
Industrial School near Lancaster. Interpreted as we 
have indicated for the Ohio Institution for girls, we find 
100, or 15%, in the group testing presumably deficient and 
179 in the doubtful group, a total of 42% clear and ques- 
tionable. 

In the corresponding Michigan Industrial School at 
Lansing, Dr. Crane (37) shows by his table of mental and 
life-ages that 52 out of the 801 unselected inmates, or 
6% are presumably deficient and 171 below the presum- 
ably passable, or 21%. This is only a slightly greater 
number than our criterion would provide, if .8 of a year 
were not classed in the next higher mental age by these 
examiners. The age of those examined ran from 10 to 17. 



146 DEFICIENXY AND DELINQUENCY 

T. L. Kelley in his "Mental Aspects of Delinquency"* 
gives the results for an extensive series of measurements 
and tests on about three hundred boys in the Texas State 
Juvenile Training School. On the basis of an analysis 
of his tests he estimates that 20% of the boys there should 
be in a school for the feeble-minded. Interpreting his 
original data for the 1911 Binet tests on the same basis 
as our own, 8% fall within the clearly deficient group and 
9% in the doubtful. The latter on account of their de- 
linquencies might also be included as feeble-minded. 

The 215 inmates of the Whittier State School in Cal- 
ifornia were examined by J. Harold Williams with the 
Stanford revision of the Binet scale (61). The boys were 
10 to 22 years of age, median 16 years. He states that 
32% were feeble-minded in the sense of having Intelli- 
gence Quotients less than .75. This is a standard which 
would include about 2% of those tested with the scale, 
so that we may consider the bulk of them as within our 
presumably deficient and uncertain groups combined. 
He also states that approximately 14% tested below X 
with the Stanford Revised Scale. In another paper he 
shows that the amount of feeble-mindedness was much 
different among the different races represented in the 
institution. With 150 cases according to his standard 
there were 6% feeble-minded among the whites, 48% 
among the colored, and 60% among the Mexican and 
Indian races. In this group 64% were native whites, 
21% of Indian or Mexican descent and 15% colored. 
"While the negro population of California constitute but 
0.9% of the total, yet the results of this study indicate 
that more than 15% of the juvenile delinquents commit- 
ted to the state institution are of that race." It is, of 
course, of fundamental importance in regard to all esti- 

*Bull. Xo. 1713. University of Texas, 1917, p. 125. 



DELINQUENTS TESTING DEFICIENT 147 

mates of feeble-mindedness among delinquents to con- 
sider the racial conditions at the particular institution. 

A New Hampshire Commission tested the children in 
its State Industrial School. Its table shows that among 
the 113 boys tested at least 37% were presumably or 
doubtfully deficient. To these should be added some 14 
years of age and over who tested X, in order to have the 
total number below our borderline for the persumably pas- 
sable cases. The published table does not separate these 
from the 13-year-olds {40). Hauck and Sisson report 
in School and Society for September, 1911, tests made at 
the Idaho Industrial School, which receives both boys 
and girls from 9 to 21 years of age, including some chil- 
dren who would be classed as dependents but can not be 
cared for elsewhere in the state. Supposing that our 
standard applied to the 1911 scale which was used, among 
201 tested there were 5 presumably deficient and 13 
doubtful. 

A partially selected group of 341 inmates at the St. 
Charles, 111., State School for Boys chosen in such a way 
that it naturally would somewhat increase the frequency 
of deficiency, was tested by Dr. Ordahl with Kuhlman's 
form of the 1911 scale supplemented by the Stanford 
Scale above XII. The results showed 11% in the pre- 
sumably deficient group and 20% in the doubtful group 
(41). 

One of the main uses of the objective scale is to dem- 
onstrate that the same conditions do not prevail in various 
institutions which, except for this objective evidence, 
might be expected to care for the same type of inmates. 
This is illustrated by the comparison of the above studies 
in Ohio and Michigan with that made at a similar state 
school for delinquent boys in Indiana reported by Hick- 
man (12, 28). The Binet 1911 tests, Goddard's adapta- 



148 DEFICIENCY AND DELINQUENCY 

tion, were applied to 229 new boys 8 to 17 years of age 
inclusive, admitted to the Indiana Boys School at Plain- 
field. Among these, 68 boys (30%) tested below our 
borderline for the clearly deficient and 53 more within 
the doubtful region, a total of 48%. There seems little 
doubt that this represents a significant difference from 
the condition at the corresponding Ohio and Michigan 
schools where only 15% and 6% respectively tested clearly 
deficient on a corresponding standard. An interesting 
commentary on the necessity of reinterpreting the border- 
line for feeble-mindedness on the scale arises when we 
note that Hickman says: "One hundred and sixty-six, 
or about 75% of the whole number tested, tested as much 
as three years or more below normal, and therefore would 
be classed as feeble-minded to a greater or less degree/ ' 

(d) MEN AND BOY DELINQUENTS IN COUNTY AND 
CITY INSTITUTIONS. 

It seems likely that in city and county institutions de- 
ficiency is most common among repeaters in the jails or 
workhouses. One study has been made of a randomly 
selected group of repeaters who were in the jail of a Vir- 
ginia city for fixed sentences of not more than a year. 
The examinations are summarized in the Special Report 
of the Virginia State Board of Charities and Corrections 
(58). In this Virginia city 50 whites of both sexes and 
50 negroes of both sexes were examined. Among the 
whites, 18 tested IX or under and 5 more tested X. 
Among the negroes, 24 tested IX or under and 10 tested X. 
The percentages would be just twice these numbers, a 
total of 61% below passable capacity in this group of 100. 
If such is the condition in other jails in other parts of the 
country, it indicates one of the most serious hot beds of 
deficiency among delinquents. The repeaters in this 



DELINQUENTS TESTING DEFICIENT 149 

city jail during three years were responsible for 60% of 
the commitments to jail, although only about one-fourth 
of the 33,306 arrests in this city during the three years 
resulted in commitment to jail. The feeble-mindedness 
among the repeaters, therefore, may be little indication 
of the frequency of deficiency among those arrested in 
the city. The repeaters represented only a third of those 
committed to jail during this period and this third was 
probably the most deficient among those committed, 
since recidivism goes with deficiency. Moreover, those 
committed to jail are probably more likely to be deficient 
than those who escape jail sentences. To assume, there- 
fore, that 61% of this city's delinquents were of doubtful 
ability would be clearly unjustified, and yet this sort of 
reasoning about the frequency of deficient delinquents 
has been all too common. 

Gilliland* tested one hundred male inmates of the Col- 
umbus, Ohio, Workhouse (28 negroes) selected so as to 
attempt to represent the different offenses about in their 
proportions. He gives the results in point scores with 
the Yerkes-Bridges scale, which may be translated only 
roughly into Binet 1911 ages by Haines' data, as I have 
indicated for the study by Rossy. All were 18 years of 
age or over, so that I estimate 14% would fall into our 
presumably deficient group including only the proportion 
of those under 64 points who would test as Binet IX or 
less. The doubtful group would include 17% more, 
including the proportion under 66 points who would test 
X or under. 

Among the local institutions supported by the county or 
city, the most serious delinquency is probably found in the 

*A. R. Gilliland. The Mental Ability of One Hundred Inmates of 
the Columbus, (O.) Workhouse. J. of Crim. Law and Crim., 1917, 
7, pp. 857-866. 



150 DEFICIENCY AND DELINQUENCY 

group reported by Kohs at the Chicago House of Correc- 
tion (33). He tested with the 1911 Binet scale 335 con- 
secutive cases between 17 and 21 years of age. Among 
these were 72 cases (21%) who tested clearly deficient 
according to our standard, and 95 cases doubtful, a 
total of 50% at least uncertain in intellectual ability. 

Through the courtesy of Catherine Mathews, who 
made the examinations for the psychological clinic of 
the University of Pittsburgh, which is under the direc- 
tion of Dr. G. C. Bassett, I am able to give the records of 
125 consecutive admissions to the Allegheny County 
Detention Home. The institution is known as the Thorn 
Hill School. It is situated some miles outside of Pitts- 
burgh and provides on the cottage plan for about 300 
boys. The boys are sent from the Juvenile Court for 
milder training than that at the state school. The school 
has also been found to furnish a necessary place to care 
for cases of feeble-minded delinquent boys who cannot 
be immediately admitted to the state institution on ac- 
count of its crowded condition. A detention home is also 
provided in the city for juvenile court children awaiting 
trial or the disposition of their cases. These are not in- 
cluded in the Thorn Hill group. 

Among the 125 consecutive cases at Thorn Hill, omit- 
ting two cases which are probably dementia praecox, 
there were 37, or 29%, who tested presumably deficient 
according to our standard, and a total of 68 cases, or 55%, 
presumably and doubtfully deficient. It is to be remem- 
bered that our standard for the immature was arranged 
for the 1908 scale and not the 1911 scale which was used 
here, although the difference would be slight. 

The accompanying Table X shows the distribution, 
omitting the dementia praecox cases. It classes .8 as 
in the next higher test age and shows the last birthday 



DELINQUENTS TESTING DEFICIENT 



151 



TABLE X. 

Binet 1911 Tests of Boys Consecutively Admitted to the Alle- 
gheny County Detention Home at Thorn Hill. (Mathews) 



Life- 
Ages 


Mental Ages 




IV 


V 


VI 


VII 


VIII 

1 

2 
3 
3 
3 

1 
2 

15 


IX 

3 
5 

8 
4 
4 
4 
1 

1 


X 


XI 


XII 


Totals 


18 
17 
16 
15 
14 
13 
12 
11 
10 
9 
8 




1 




1 
1 








2 
3 

7 
8 
6 
3 
4 
1 
2 

36 


1 
7 
8 
5 
4 
1 

26 


2 
1 
1 
2 
3 
1 

10 


2 

10 

22 

29 

22 

18 

10 

3 

4 

3 


Totals 


1 




2 







4 


30 


123 



for life-age. In interpreting these figures it is highly im- 
portant to remember that Thorn Hill is necessarily used 
at present to shelter deficient boys who are dependent or 
delinquent and cannot be otherwise provided for. This is 
undoubtedly a wise temporary relief until the state takes 
proper care of these unfortunates. Under the cottage 
system which prevails at Thorn Hill the segregation can 
be made with little interference with the main purpose 
of an institution for delinquents. It is apparent that any 
deductions made from the large frequency of feeble- 
mindedness among these delinquents without consider- 
ing the particular local conditions under which they are 
found, would be wholly unjustified. A similar local con- 
dition probably explains the high percentage of tested 
deficiency among the following group of boys in the 
Newark, N. J., detention home. 



152 DEFICIENCY AND DELINQUENCY 

A representative group of 100 in the detention home at 
Newark, * 'chosen entirely at random/ ' was examined by- 
Mrs. Gifford, and reported by herself and Dr. Goddard 
(17). In this group of 100 there were 66 between the 
ages of 14 and 17 who were at least four years retarded 
mentally. Moreover, among these 66 "none tested 
over eleven and only a few at that age." Only average 
mental ages are published, so that we cannot tell how many 
tested XI or X, but the statement quoted shows that few 
of these 66 would test XI, and would thus be above our 
doubtful class. We may, perhaps, suppose that about 
66% of this group in the Newark detention home tested 
as low as the randomly selected group at Thorn Hill, 
Pittsburgh. 

That the explanation of the excessive amount of de- 
ficiency found at Newark lies in the inadequate provision 
for recognized feeble-mindedness in that community is 
indicated by the Fourteenth Annual Report of the New- 
ark City Home. It states that "the lack of a state in- 
stitution for defective children made it necessary to com- 
mit to the City Home many children, who, on account of 
physical defects and psychic disturbances, have become 
juvenile delinquents/ ' A statistical table shows that of 
181 boys, 151 were either illiterate or below the fifth 
grade in school in spite of the fact that the average age 
of the boys at the school is 13 years. This shows clearly 
that the differences between the test results at this in- 
stitution and those in Minneapolis, Chicago, and else- 
where, is not the result of different methods of giving the 
tests. It seems to be mainly due to inadequate state 
provision for recognized feeble-minded children. 

Among the more serious juvenile court offenders we 
have a group of 1000 recidivists referred to Dr. William 
Healy at the Psychopathic Institute connected with the 



DELINQUENTS TESTING DEFICIENT 153 

Chicago Juvenile Court. The cases are not tabulated 
separately for the sexes as to mentality. They were all 
under 21 and averaged between 15 and 16 years of age. 
While he used the Binet tests quite generally, as well as 
his own and Miss Fernald's series (I 25), Dr. Healy has 
not summarized his data in reference to the test standards. 
Nevertheless, according to his experience after the results 
of the test examinations were known, he classified only 
89 of these cases as moron and 8 imbecile, a total of only 
9.7% feeble-minded. Another group above these amount- 
ing to 7.9% was classed as of "subnormal mentality — 
considerable more educability than the feeble-minded" 
(27, p. 139). 

From the same psychopathic laboratory comes the es- 
timates of Dr. Bronner (7) of a group of less serious of- 
fenders, some of whom were in court for the first time, a 
group at the Cook County Detention Home connected 
with the Juvenile Court in Chicago, where cases are held 
for trial or until other disposition can be made of them. 
I have already reported her results with the Binet tests 
for the girls in this group. Using the same standard 
which was there described, she found among 337 boys 7 
to 16 years of age 7% "probably feeble-minded/ ' and 
2.4% doubtful, a total of 9.4% "possibly feeble-mind- 
ed.' ' As nearly as I can tell from the description of 
the borderline which she used with the tests, a boy was 
perhaps slightly more likely to be regarded as testing 
probably deficient than by our standard for the presum- 
ably deficient. Inasmuch as Miss Bronner worked with 
Dr. Healy, this may throw some light on the test standard 
which he had in mind in connection with his more serious 
offenders. 

By means of Bluemel's study of different classes of 
juvenile delinquents who passed through Judge Lind- 



154 DEFICIENCY AND DELINQUENCY 

say's Juvenile Court in Denver, we are able to compare 
the intellectual ability of a group which was on probation, 
about half of whom were first offenders, with groups sent 
to the Boy's and Girls' State Industrial Schools (2). 
Although the report does not so state, I should judge that 
the cases were objectively selected. The published data 
is not adequate to state the results on the basis of our 
conservative borderlines; but we can note the cases 
which tested XI or below and were four or more years 
retarded with the 1911 Binet Scale (Goddard's modifica- 
tion). This only differs from my broadest interpreta- 
tion by also including those that test XL On this basis 
6 of the 100 probationers were possibly deficient; 9 of the 
50 boys sent to the State Industrial School, and 24 of the 
50 girls sent to the State Industrial School or Florence 
Crittenden Home. These are all somewhat excessive 
estimates of the amounts of deficiency in this group as 
judged by the interpretation we have been using. A 
more telling comparison of the mentality of these groups 
may be made by weighting each retarded case by the tests 
according to the number of years he is retarded. The 
amount of retardation alone averages 1.3 years for the 
group of probationers, 1.8 for the boys at the state school, 
and 3.8 years of the institutional group of girl delinquents. 
Fifty first offenders among the probation group average 
1.1 years retarded. The girls and the more serious 
juvenile delinquents in these younger groups show more 
retardation. 

The Stenquist, Thorndike, and Trabue study of chil- 
dren 9 to 16 years of age, who were county charges as 
delinquents or dependents in a single county, provides 
results for a group of 104 delinquent boys. Translating 
their records as I have explained for the girls in the group, 
we find 11 of these presumably deficient and 18 doubtful, 



DELINQUENTS TESTING DEFICIENT 155 

a total of 28%. So far as their delinquency is concerned 
these probably correspond to the local institution groups. 
While there is little difference in the average mentality of 
the groups of delinquent and dependent children in this 
county shown by tests there is apparently some difference 
in the frequency of serious deficiency. In their corres- 
ponding group of 63 dependent boys who were county 
charges, 2 are in the presumably deficient group and 10 
in the doubtful, a total of 19%. Miss Merrill found only 
0.8% in our presumably deficient group and 1.6% un- 
certain in a group of 250 dependent children at the Min- 
nesota State home (149). 

Dr. Pintner reports the examination of 100 cases in 
the Columbus, Ohio, Juvenile Court who were in the 
detention home waiting to be disposed of or held for trial. * 
He does not say whether they were selected cases among 
those in the home, but we may presume that they were 
more serious offenders than the usual juvenile court cases 
not in the home. Their ages ranged from 7 to 20 years. 
He used the Binet 1911 series and allowed double credit 
for any test passed in the XV or adult series. By placing 
his borderline so that a person testing 3.1 years retarded if 
he scored under XII would be regarded as feeble-minded, 
Dr. Pintner found 46% feeble-minded in this group. 
Under the same standard about 20% of the Minneapolis 
group would be classed as feeble-minded, instead of 2 to 7% 
under our more conservative borderlines. 

In a preliminary report of the doctorate examination 
of Dr. Olga L. Bridgman (132) I find that she reports 
testing 205 delinquents and 133 dependent children sent 
to the psychological clinic of the University of California. 
She found 36% of the delinquent and 26% of the dependent 

*R. Pintner. One Hundred Juvenile Delinquents Tested by the 
Binet Scale. Ped. Sem., 1914, XXI, 523-531. 



156 DEFICIENCY AND DELINQUENCY 

cases thus especially selected for clinical examination to 
be "definitely feeble-minded,' ' but the preliminary report 
does not enable one to judge the standard used for her 
borderline (3). 

Ordahl's study* of 61 cases who were wards of the San 
Jose Juvenile Court is not comparable with other groups 
since both sexes, both dependents and delinquents and 
ages from 3 to 44 were included. 

Dr. Hickson (5) reports concerning some 2700 cases 
selected especially for examination from those passing 
through the municipal court in Chicago, in the divisions 
of the Boys Court, the Morals Court and the Domestic 
Relations Court. His tables state only average mental 
ages, and he classes 728 boys who average XI. 11 as 
morons, so that I am unable to make any comparisons 
with his data. 

Dr. Walter S. Cornell (92) published in 1912 the re- 
sults of Binet tests on 100 cases at the Philadelphia House 
of Detention among whom 64% tested three or more 
years below normal and 41% four years or more below 
normal. We are unable to tell how many of these tested 
X or above and were thus of questionable deficiency. 
He also gives the results merely with the years of retarda- 
tion for a group of 73 "mildly delinquent boys of Miss 
Wood's special school and the Children's Bureau (mostly 
truants)." Of this group 46% were three years or more 
and 25% four or more years retarded according to the 
tests. Again we are unable to judge how the cases were 
selected or what was the mental age distribution so as to 
discover those that fall under our borderlines, especially 
under the borderline of XI for the mature. 

Psychological examinations have been employed in con- 

*George Ordahl. Mental Defectives and the Juvenile Court. J. of 
Delinquency, 1917, II, 1-13. 



DELINQUENTS TESTING DEFICIENT 157 

nection with the children at the Seattle Juvenile Court. 
Although the results are not presented in a form which 
can be compared with other localities, Dr. Merrill, the 
physician who directs the general clinic, is of the opinion 
that feeble-mindedness was the cause of the delinquency 
of only 6% of 421 consecutive cases (148). Previously 
in the same court, Dr. Smith, the psychologist, on the 
basis of tests, reported among 200 consecutive cases only 
11 cases as feeble-minded, 5 as mentally defective, and 8 
as "moral imbeciles/' a total of 13.5% (53). 

Frau Dosai-Revesz (13) gave a number of tests to 40 
boys, 9 to 16 years of age, selected from the boys train- 
ing school of the Children's Protective League in Hungary. 
The cases which she classified as morally feeble-minded 
were found to test between the normal and the feeble- 
minded groups. 

As yet only the preliminary announcement has ap- 
peared of a study of a thousand delinquent boys and girls 
with the Point Scale which has been made by Bird T. 
Baldwin. It is to be published as a Swarthmore College 
Monograph (Psychol. Bui., 1917, 14, p. 78). 

The reader should also consult the series of articles 
by L. W. Crafts and E. A. Doll appearing in the Journal 
of Delinquency beginning with May, 1917, on 'The Pro- 
portion of Mental Defectives among Juvenile Delin- 
quents/ ' It is especially valuable as a critique of the 
conditions desirable for exact comparison of the results 
of different investigations. 

A Bibliography of Feeble-Mindedness in Relation to 
Juvenile Delinquency, compiled by L. W. Crafts, may be 
found in the Journal of Delinquency, Vol. I, No. 4. In 
Chap. II of his Problems of Subnormality, Dr. Wallin gives 
an admirable review of numerous studies of tested groups. 



158 DEFICIENCY AND DELINQUENCY 

C. Summary of Tested Deficiency 
Among Delinquents 

In bringing together these studies in which we can 
make somewhat comparable estimates of tested deficiency 
covering over 9000 delinquents, it seems possible to 
analyze further the question of the deficient delinquent. 
Comparison of the amounts of deficiency on an objective 
basis is scientifically a big step in advance from a reliance 
upon the subjective opinion of experts who cannot pos- 
sibly have the same standard of deficiency in their minds. 
The results of the comparable investigations, on the basis 
of the above reinterpretation of the borderlines, are 
brought together in Table XL The frequency of tested 
deficiency which is found among about the lowest 0.5 
and 1.5% respectively of the population generally is 
there shown for these different groups of delinquents. 
This review of the studies thus assembled enables us to 
correct a number of impressions that have become prevalent 
by the early studies, as well as to formulate the general 
data in regard to the deficient delinquent in a manner 
that places the practical control of this problem on a 
safer foundation. We shall summarize the data under 
four heads. 

1. Intellectual deficiency as a social problem is un- 
doubtedly at present most serious among women and 
girls who are sex offenders. It is this fact which accounts 
for the excessive amount of deficiency found in the in- 
dustrial schools for girls, and the reformatories for wo- 
men. It is not necessary to repeat the discussion of the 
reasons for this which were considered at the close of the 
studies of women delinquents. The most closely cor- 
responding class of male delinquents is probably the 
"vags," as Aschaffenburg suggests {68, p. 162). The 



DELINQUENTS TESTING DEFICIENT 



159 



TABLE XL Frequency of Tested Deficiency Among Over 9000 
Delinquents. 

Comparison of the frequency of tested deficiency among objectively selected 
groups of delinquents reinterpreted on roughly the same borderlines, 
which are often not those used by the original investigators. "Pre- 
sumably deficient" in the table corresponds roughly to about 
tlie lowest 0.5 per cent., and the doubtful group to about 
the next 1.0 per cent, in the general population 





No. ! 
of 


Percentages 




Presum- 






Group and Investigator 


Cases 


ably de- 
ficient 


Doubt- 
ful 


Both 


Women and Girls 










State Institutions 










Penitentiaries 










Illinois Penitentiary (L. E. and G. Ordahl) Negro 


26 


15 


27 


42 


Same White 


23 


9 


30 


39 


Reformatories 










Bedford Reformatory, N. Y. (Weidensall) 


20C 


38 


37 


75 


Same (M. R. Fernald) 


100 


41 


24 


65 


Western House of Refuge, N. Y. (Herrick) 


194 


(25) 


(14) 


(39) 


Training Schools 










State Home for Girls, N. J. (Otis) Partially 










selected 


172 






(68) 


Girls Industrial Home, Ohio (Renz) 


100 


(29) 


(20) 


(49) 


State Industrial School and Florence Crittenden 










Home, Colo. (Bluemel) 


50 






(48) 


N. Y. Training School for Girls (Hall) 


607 


(20) 


(28) 


(48) 


Girls Industrial Home, Ohio (Haines) 


329 


21 


17 


38 


Illinois State Training School for girls (L. E. and 










G. Ordahl) 


432 


13 


22 


35 


Industrial School for Girls, Mich. (Crane) 


386 


14 


20 


34 


California School for Girls (G. M. Fernald) 


124 






19 


County and City 










Sex Offenders 










Sex Offenders not under arrest, Albany, N. Y. 










(McCord) 


88 


32 


35 


67 


Unmarried mothers, Cincinnati General 










Hospital (Weidensall) 




(48) 






Professional prostitutes, Mass. (State Commission) 


300 


27 


33 


60 


Prostitutes in a segregated district in a Virginia 










City (State Commission) 


120 


36 


20 


56 


Juveniles 










Cook County Juvenile Detention Home, 










Chicago (Bronner) 


133 


11 







160 



DEFICIENXY AND DELINQUENXY 



TABLE XL— Cor.::rued 



No. 
of 



Group and Investigator 



Presum- 
ably ce- 

ncie::: 



Doubt- 
ful 



Both 



Men and Boys 

mate Institutions 
Penitentiaries 

Llircis Perdrertiary Ordahl 
Ohio Per::er.::ar.- Hair.es 
S:a:e Prison, Mass. Rossv 

Rr:~ ■■■:. ■;■.,; 
Sia:e Reformaiorv. M:rre.sota Greer. 
State Reformatory, Iowa (Report) 

Ir.diar.a Beys Schcol Hickrrar. 
Boys Indusrral 5chx>'.. Ohio Hair.es 
State Industrial School, Colo. (Bluemel) 

Whi::ier 5:a:e Schxl, Calif. Wiiliarrs 






N. 



Re- 



;inia city (State Com- 



Chicae 
Coliir£ 



Allegheny Lour. 
B:ys clrti'firj 
Cx^C:ur.:y D 

Cour:v. M 
Probationers. J- 



:ior Kohs 
2-'*Nf-£- ; 

!, N. J. (Gifford and 

les Detention Here, 
ir.'.y Stenouist. Thorr.- 



r.epir 



51 

s; 

300 

99G 

229 

671 

50 

2:5 
341 

s-:: 

147 
296 



50+ 
50f 

335 

100 



100 

125 

104 

337 

123 
100 



25; 



13 
20 

3? 
15 

(14) 

(11) 

6 



48 
36 
21 
(14) 



29* 

11 
7 
2 



(11) 



22 

15 

18 
27 

(18) 
(20) 

15 



20 
10 
29 
(17) 



26* 
17 



>36 
18 
16 

35 
35 

48 

42 

W 

32 
(31) 

21 
37- 

17 



63 
46 
50 
(31) 



6-5 ~ 
55* 
28 



7 
6 



*Local conditions explain the excessive amount of deficiency. 
Parentheses indicate percentages or selection on a somewhat dif- 



DELINQUENTS TESTING DEFICIENT 161 

vagrants form a much smaller portion of the inmates of 
the institutions for male delinquents than do the prosti- 
tutes in the institutions for women and girls. The little 
evidence we have indicates, moreover, that as a class 
the ne'er-do-wells average higher in ability than the pros- 
titutes. They are, probably, a more mixed group. As 
reported by Terman (57), Mr. Kollin found among 150 
1 'hoboes' ' at least 20 per cent belonged to the moron grade 
of mental deficiency/ ' * * * 'The above find- 
ings have been fully paralleled by Mr. Glen Johnson and 
Professor Eleanor Rowland, of Reed College, who tested 
108 unemployed charity cases in Portland, Oregon' ' (57, 
p. 18). Since these investigators used the Stanford Scale, 
the borderline was probably set at the position where it 
would exclude about 1% of the ordinary population, a 
little more conservative than our doubtful group. We 
should know more about deficiency among the typical 
"Weary Willies/ ' since it is likely that courts are accustom- 
ed to assume that vagrancy is a habit which can be cor- 
rected by a term in the workhouse. There is little doubt 
that mental deficients fill up the recruiting stations for 
the prostitutes and "vags." It is with these classes that 
the most intensive social work should be done in the 
campaign for early isolation of the unfit. 

2. Institutions which care for the same type of delin- 
quents show pronounced variation in the amount of tested 
deficiency. Compare the Indiana Boys' School with the 
Michigan Industrial School for Boys. Thirty per cent, 
tested presumably deficient in the former as against 6% 
in the latter; or 48% in the former and 21% in the latter 
tested below our borderline for the presumably passable 
intellects. This difference can hardly be explained by 
errors in testing. It marks a significant difference be- 
tween the care of the mentally deficient in the two states. 



162 DEFICIENCY AND DELINQUENCY 

The difference in the success of states in isolating their 
feeble-minded is best shown by comparing the Newark 
and Pittsburgh institutions for boys from the juvenile 
courts on the one hand, and the local groups of boy de-* 
linquents from Hennepin County, Minn., and Cook Coun- 
ty, 111., on the other. In one case over 60% and in the 
other less than 10% were below the same borderline. In 
other words, the courts in Newark and Pittsburgh were 
deliberately sending mental deficients to their local in- 
stitutions for delinquents because there was no better 
place available, not because they mistook deficiency for 
delinquency. The better diagnosis of deficiency by test 
criteria is, however, the first step in demonstrating this 
situation so that public sentiment for an adequate state 
care for the feeble-minded may be in accord with a con- 
servative statement of the present conditions. More- 
over, we have made real progress when we have demon- 
strated objectively that the difference in the character 
of the inmates of corresponding institutions is not a mere 
matter of opinion. 

3. Unfortunately for social reform, a wholly incorrect 
impression seems to have spread abroad that half of the 
delinquents in juvenile courts are feeble-minded. Exag- 
geration of the condition retards rather than assists a 
sane public policy regarding the indefinite isolation of 
those demonstrably deficient by psychological tests. 
The mistaken impression apparently started with the 
study of Goddard and Gifford as to the condition found 
among boys at the Newark Detention Home. Two- 
thirds of these boys tested approximately below our border- 
line for clearly passable intellects. I should not be in- 
clined seriously to question calling these two-thirds in the 
Newark Home feeble-minded, since I am willing to class 
those in our doubtful group as feeble-minded provided 



DELINQUENTS TESTING DEFICIENT 163 

that they are persistent delinquents. The deductions 
which were drawn from this startling discovery seem, 
however, to have slipped into the literature of the subject 
without anybody noting that they were unjustified by 
the facts. In the first place the condition at Newark 
Detention Home may reflect a peculiar local situation 
analogous to that at Pittsburgh in which deficient boys 
had to be cared for in the detention home because no 
other institution was available for these feeble-minded. 
Under these recognized local conditions, it would seem 
that the general situation might be better represented by 
the conditions of deficiency found since then in Cook and 
Hennepin counties than by the conditions at Newark. 
We at least know that Newark and Pittsburgh represent 
special and not ordinary conditions among those in local 
detention homes, unless the situation is very different in 
the East from that in the West. 

Besides regarding the condition in the Newark Deten- 
tion Home as representative of the general condition in 
detention homes elsewhere, it was argued that the con- 
dition in the detention home represented the condition 
among the ordinary cases of delinquents before the juv- 
enile courts. The groups in detention homes are un- 
doubtedly extreme both as to the seriousness of their 
delinquency and as to their deficiency. Since Goddard 
published his paper following the Newark study consider- 
able additional evidence has been made available. But 
even without this contradictory data, it was a big jump 
to assume that the condition in the local detention home 
represented the frequency of deficiency among the ordin- 
ary cases which come before the juvenile courts. 

Either Dr. Goddard overlooked this distinction between 
serious offenders who are often repeaters and the ordinary 
offenders, or he took the questionable position that the 



164 DEFICIENCY AND DELINQUENCY 

difference was unimportant. On the basis of the tests of 
cases in the detention home in Newark, which we have 
quoted, he says that "by actual test 66% of the children 
in the Juvenile Courts of Newark are feeble-minded." 
Again after quoting the results of examinations of delin- 
quents at several institutions, he says: "Suppose we take 
the very lowest figure that any of these studies suggests, 
namely 25%, and see for a moment where it leads us. 
Twenty-five per cent, of the children who come before the 
Juvenile Court"" are feeble-minded. The figures cannot 
be less than that" {19). 

This paper was subsequently referred to by Dr. Fer- 
nald, physician at the Massachusetts Reformatory, as 
follows: "It has been found by the most eminent research 
workers in this field that probably not less than 25% of 
the criminals who come before our courts are feeble- 
minded and that a much larger percentage of the children 
brought before the Juvenile Court are defective" (103) * 

The incorrectness of the assumption that detention 
home cases show no more deficiency than ordinary juv- 
enile court cases could not at the time be demonstrated. 
Since then, however, there have been several objective 
studies. In Minneapolis we found that relatively twice 
as large a proportion of the serious offenders sent to the 
county detention home were either three or four years re- 
tarded in school as we found among the ordinary juvenile 
offenders taken consecutively. The data will be presented 
later under our discussion of the school test. We also 
found that if we compared the results of Binet examina- 
tions at the Minnesota reformatory (22) with those at the 
county detention home, tested deficiency is about five 
times as common among the older and more established of- 



*Italics mine. 



DELINQUENTS TESTING DEFICIENT 165 

fenders at the reformatory. At Chicago serious deficiency 
was less frequent among those in the detention home than 
among more serious recidivists. Bluemel, as we have 
also noted, found that the frequency of tested retardation 
was decidedly greater among boys in Denver sent to the 
State Industrial School than among those only put on 
probation in that city. The investigation of Stenquist, 
Thorndike and Trabue shows that serious deficiency is 
less among dependent boys than among delinquents in 
the same county. Cornell found less truant boys de- 
ficient than delinquent boys, in the Philadelphia House of 
Detention. In Chicago, Denver and Minneapolis, more- 
over, less than 10% of the more serious cases in the de- 
tention homes were found deficient. This evidence all 
tends to contradict the assumption that a large propor- 
tion of the ordinary children brought before the juvenile 
court is feeble-minded. 

Ernest K. Coulter, as Clerk of the Children's Court of 
New York County, has raised his voice in protest against 
charging the Juvenile Courts with dealing mainly with 
feeble-minded children. He says: 

'The writer, who has seen at close range 80,000 chil- 
dren pass through the largest Children's Court in the 
world, has little patience with the sentimentalist who 
would pounce on every other juvenile delinquent as a 
mental defective' ' (94, p. 68). 

Unless we are to convert valuable propaganda for iso- 
lating the feeble-minded from good kindling wood into 
shavings, we must remove this cloud which has been cast 
upon the mentality of the ordinary children who are 
brought before juvenile courts of the country. Travis, 
(202) years ago, may have been nearer right when he 
said that 95% of the children who come before the Juv- 
enile Court are normal. Surely this agrees better with 



166 DEFICIENCY AND DELINQUENCY 

the conditions found in Chicago, Denver, and Minneapolis. 
Possibly these western cities, however, show unusually 
good conditions. The evidence as to the peculiar local 
situations in Newark and Pittsburgh makes one confident 
that their detention home conditions do not at all repre- 
sent the frequency of mental deficiency among ordinary 
juvenile offenders in these cities. I see nothing in the 
present evidence from mental tests to indicate that the 
frequency of mental deficients who might justly be sent 
to institutions from among the ordinary children who 
come before the juvenile courts of the country, would be 
over 10 per cent. 

4. What shall we say as to the general frequency of 
deficiency among delinquents of all classes? How about 
the impression that a large proportion of them are not 
responsible because of their deficiency and that the con - 
dition is worse among juveniles? Note some of the pub - 
lished statements: "Probably 80% of the children in the 
Juvenile Courts in Manhattan and Bronx are feeble- 
minded/ ' "Preliminary surveys have shown that from 
60% to 70% of these adolescents [sent to the industrial 
schools in one state] are retarded in their mental develop- 
ment and are to be classed as morons/ ' "Forty to 50% 
of our juvenile delinquents are without a doubt feeble- 
minded/ ' "The best estimate and the result of the most 
careful studies indicate that somewhere in the neighbor- 
hood of 50% of all criminals are feeble-minded/ ' "Near- 
ly half of those punished for their wickedness are in reality 
paying the penalty for their stupidity/ ' "More than a 
quarter of the children in juvenile courts are defective." 
"One-third of all delinquents are as they are because they 
are feeble-minded/ ' "It is extremely significant in the 
study of juvenile delinquency that practically one-third 
of our delinquent children are actually feeble-minded ." 



DELINQUENTS TESTING DEFICIENT 167 

Fortunately, some of these writers are already begin- 
ning to qualify and modify their views, and some of these 
statements misstate the idea of the investigators, but it is 
difficult to correct the impression that has been gathered 
from those who speak with authority. In the face of 
the fact that mental deficiency is undoubtedly the most 
important single factor to be considered today in the 
institutional care of delinquents, one hesitates to correct 
even the most exaggerated impressions as to its import- 
ance. On the other hand, it seems time to modify opinions 
which raise false hopes as to solving the problem of de- 
linquency by caring for the feeble-minded. Above all it 
is important to lay a surer foundation on which a platform 
for the social care of these unfortunates may be securely 
built. 

In the first place, it is necessary to recognize that after 
all the feeble-minded are properly cared for by society the 
problem of the ordinary delinquent may still remain with 
us in much of its present proportions. Surely the isola- 
tion of the deficient children will hardly scratch the sur- 
face of the problem of first offenders as it comes before 
the juvenile courts of the country. To this it should be 
replied that the first offenders are not, after all, the trouble- 
some cases before our courts. If we study the different 
groups of delinquents which have been tested, we notice 
that they represent highly selected groups among the 
ordinary offenders whether these be adults or minor de- 
linquents. The only parallelism which can be traced at 
all is between prostitutes and vagrants and some of the 
institutional groups. We should stop assuming that the 
institutional delinquents represent the ordinary offenders. 
The present evidence points to the conclusion that it is 
the repeaters, not the first offenders either in the juvenile 
of criminal courts, who are most likely to be deficient. 



168 DEFICIENCY AND DELINQUENCY 

Nevertheless, 68% of the boys brought before the Chicago 
Juvenile Court during its first ten years were first offend- 
ers (142), while 89% of 4143 boys in the Juvenile Court 
in Minneapolis were first offenders (105). We know al- 
most nothing about the frequency of deficiency among 
the first offenders brought before our courts and yet the 
bulk of delinquents are undoubtedly first offenders. 

On the other hand, the repeaters do account for a con- 
siderable portion of the cases before the courts, especially 
the municipal courts, because each offender appears time 
and time again. In the Virginia city cited, for example, 
repeaters furnished 60% of the jail commitments for three 
years. This is probably also an indication of the work- 
house situation, which is best represented by such a study 
as that of Kohs. The proportions of offenses accounted 
for by deficiency would, therefore, be much larger than 
the proportion of offenders who are deficient. While the 
offenses of repeaters might not commonly be serious 
crimes, they afford a serious problem because of their bulk 
and because temporary restraint is of little use when the 
offender is mentally weak. As Aschaffenburg says: "We 
must not forget that it is not the murderers, not the swind- 
lers, on a large scale, not the assassins of people in high 
places, and not the sexual murderers, that determine the 
criminal physiognomy of our day, but the thieves and 
pickpockets, the swindlers and abusers of children, the 
tramps and the prostitutes" (68, p. 181). 

The best that we can do is to study Table XI, which 
gives us a classified list of different types of delinquents 
in institutions. If we Should pick out in it such institu- 
tions as represent to us the typical conditions in the coun- 
try we could get an idea of what we might expect from 
groups of offenders of each type. For example, we might 
say that the Massachusetts State prison is typical of such 



DELINQUENTS TESTING DEFICIENT 169 

institutions, and it contained possibly 16% who were de- 
ficient. Picking the Ohio Boys Industrial School as typ- 
ical of its class, it had between 15% and 42% deficient, 
depending on how conservative you wish to be in your 
diagnosis. So one might go through the list stating the 
expectation for each type of institutional delinquent. 
If these were then weighted according to the number of 
delinquents of each class in the country sent to them, we 
would have some idea of the frequency of deficiency among 
those who reach the institutions. Merely to average the 
columns in Table XI would give only a false impression. 
The seriousness of the situation is amply demonstrated 
among repeaters and the inmates of certain institutions. 
Each superintendent should be put upon inquiry as to his 
own charges. 

Nothing which I have said in caution as to the import- 
ance of deficiency in solving the problem of delinquency 
can be taken for a moment to signify that the effort for the 
isolation of the deficient is misspent. Elimination of a 
generation of deficients will not solve the problem of de- 
linquency, but in no other way is there open such a clear 
and definite method of reducing that problem. The better 
care and prevented procreation of even a tenth of the de- 
linquents who would propagate deficiency, would mean 
the most scientific advance in attacking the problem of 
delinquency. A safe public policy can be formulated 
which would at first provide for appropriate permanent 
care of at least that number of delinquents in institutions 
who by test are presumably deficient. This perfectly 
obvious first step promises to tax our facilities for years. 



CHAPTER VII. CHECKING THE BINET 
DIAGNOSIS BY OTHER METHODS 

The Binet scale in its various forms provides only part 

of the objective evidence as to the mental inferiority of 
delinquents, although it affords the best means at present 
of interpreting the borderline of deficiency. Among the 
other investigations in which psychological tests have 
been tried with delinquents in comparison with normal 
subjects, the recent study of the Mentality of the Crim- 
inal Women by Weidensall is the most important so 
far as estimating the frequency of deficiency is concerned 
(60). It affords an admirable check upon our conclusions 
from the Binet examinations, since she gives in detail the 
results with a random group of SS women inmates of the 
Bedford X. Y. Reformatory, which is quite comparable 
with the group of 20v which she tested with the Binet 
scale, and which we have already considered. 

For our purpose, the most important comparisons are 
those between the group of women in the reformatory and 

by Woolley with the same tests. Weidensalks Table 92 
shows for three tests the percentages of the Bedford wo- 
men who tested below the lowest T : 7- o: these girls. For 
the opposites test. 20-7 : were below this borderline: for 
a test on the completion o: sentences. 12-T-: for the mem- 
ory span for digits, 29%. She also shows that 17% of the 
delinquent group were poorer than any of the working 
girls and 30.7— as poor as the poorest 5.7-7- of these work- 
median working girl of fifteen. This 30.7 C 7 : is probably 
most nearly comparable in ability with the lowest 0.5 C 7 
of the general population. 
170 



CHECKING BINET DIAGNOSIS 171 

Kelley's monograph on Mental Aspects of Delinquency, 
to which reference was made in the last chapter, gives the 
results with boys in the Texas Juvenile Training School 
for the completion test and his own construction test, as 
well as for a number of physical measurements, sensory 
and motor tests. He has used various data from which 
to provide norms for comparison. In connection with 
the Psychopathic Institute at the Chicago Juvenile Court, 
Healy and Fernald (125) have published an elaborate 
series of tests with suggestions as to how they may be 
employed for analyzing a child's mental ability and esti- 
mating his mental capacity. Schmidt has partially stan- 
dardized these tests (178). Guy G. Fernald (15) tried 
out a dozen different tests and recommends seven of them 
for testing delinquents who are of adolescent age or older. 
Haines has sought the diagnostic value with girl delin- 
quents of a dozen tests including Fernald's test of moral 
judgment. Weidensall (218), Smedley (51), Rowland 
(49), Porteus (45), and Whipple and Fraser (220, p. 663), 
have published results with certain tests tried with de- 
linquents. With none of these tests can we adequately 
define the borderline of feeble-minded intellects. 

There is no series of tests which has been employed out- 
side the field of delinquency which diagnoses the border- 
line cases objectively so well as the Binet scale. The 
tests of Weygandt (219); Rossolimo (175), Rybakow (176), 
and Knox (134) are without definable limits based on 
unselected groups. Those employed by Dr. Norsworthy, 
while scientifically better scored for describing the border- 
line, were not arranged with this in view (160). Carpen- 
ter has published norms obtained with Squire's tests on 
50 pupils of each age from 7 to 14. Single tests like the 
form board (87), Knox's cube test (134), the substitition 
test (1), and the A test (160) have been tried with de- 



172 DEFICIENCY AND DELINQUENCY 

linquent or feeble-minded groups as well as with normal 
people. Under the direction of the New York Board of 
Charities an excellent beginning has been made in deter- 
mining norms for eleven different tests (158). Stenquist, 
Thorndike and Trabue (54) have furnished developmental 
norms for several tests. Gilbert (108) and Smedley (51) 
at an earlier date provided age norms and deviations for 
certain tests. Mrs. Wooley has provided the percentile 
distribution for a series of mental and physical tests with 
14- and 15-year-old children leaving the public schools to 
go to work (222) (223). In England a goodly number of 
different tests have been tried out on small groups or on 
children of particular ages (84) (63) (224). Pyle has ob- 
tained norms and variations with a series of group tests. 
It approaches nearest to the Binet as a developmental 
scale for the immature, but these tests have not been 
tried as individual tests and so could hardly be used 
safely for individual diagnosis. A graphic summary of the 
developmental curves for most of these tests on children 
will be found in Chapter XIII. 

In no case do we find any tests except the Binet scales 
which have reached a stage of practical usefulness for the 
diagnosis of deficiency except as supplementary aids for 
checking the Binet indication with children of particular 
ages. The emphasis has almost universally been placed 
on determining the central tendencies of children of differ- 
ent ages and not on the lower limits of the distributions. 
Considering mental tests apart from the Binet scale, in 
all the extended literature which has been brought to- 
gether in books like Whipple's Manual of Mental Tests 
(220), one may seek in vain for tests which have reached 
the position of defining the limits of serious mental de- 
ficiency. This indicates, of course, the difficulty as well 
as the newness of the problem, although the quantity of 



CHECKING BINET DIAGNOSIS 173 

work that is being done shows the great interest aroused. 
From all of this mass of research on mental tests one may 
gather much that is useful in analyzing the character of 
a mental defect. Many of the tests admirably aid in 
elaborating the subjective impression of the examiner. 
The failure to do this systematically has been one of the 
main criticisms raised against the Binet scale. This and 
the incorrectness of the bordlerline described in the pub- 
lished scale seem to be the main objections made by Miss 
Schmidt to the Binet Method. She voiced the objection 
of the Juvenile Psychopathic Institute in Chicago to the 
tests as follows: "It has been the experience of the writer, 
and it may be added of all others who have worked in this 
laboratory, where practical results are demanded, that 
the Binet tests cannot furnish an adequate means through 
which to come to conclusions for the disposition, classifi- 
cation, or treatment of the cases which come for diagnosis' ■ 
{179). 

Dr. Merrill of the Seattle court also seems unfriendly to 
the Binet scale when he says: "Any system of tests by 
which alone* it is attempted to classify the child as being 
of a given mental age involves the fallacy of pseudo- 
exactness, and needs carefully to be avoided' ' (148). No- 
body would seriously urge that real exactness of definition 
leads to confusion. It is just the looseness of definition 
of borderline with the Binet Scale which has led to most of 
the mistakes with it. Perhaps Dr. Merrill has not dis- 
covered that the scale works just as well when used as a 
graded series of tests without the designation of mental 
ages at all. The latter is merely a convenience. On the 
other hand, we should agree when he says, that "no scale 
of tests can give a valid measure of the child's intelligence 
unless supplemented by a consideration of his history/ ' 
especially if he includes in the child's history a medical 
diagnosis. 

*Italics mine. 



174 DEFICIENCY AND DELINQUENCY 

The objection that the Binet tests do not analyze the 
source of the child's mental defect is of course important 
if one were considering whether a better scale might not 
be devised. It is rather beside the point, however, when 
one remembers that it is not the purpose of this scale to 
determine the causes of deficiency, but only to say whether 
a deficiency in general intelligence is present and to what 
degree. The causes of the disturbance must then be de- 
termined by an expert. Moreover, if one classifies the 
Binet tests as Meumann has done one may often get valu- 
able clues as to whether the deficiency is mainly in in- 
formation or in mental process. In seeking the causes 
of the disturbance, the expert should not overlook the 
standardization of the Rozanoff and Kent Association 
Test which has been available for delinquent, feeble- 
minded and normal children (174). It is one of the most 
important supplementary means for mental analysis 
which has yet been standardized for practical use. The 
most complete tables on children's reactions for this test 
have been published in a Psychological Monograph by 
Woodrow r and Lowell. 

The importance of more accurate psychological tests in 
studying mental disturbance is well illustrated by com- 
paring the results that may be obtained with the Binet 
tests with the desultory, unstandardized tests such as 
one finds in Dr. Schaefer's Allgemeine gerichtliche Psy- 
chiatrie fur Juristen, Mediziner, and Padagogen (177), 
or Dr. CimbaTs Taschenbuch (91) prepared for physicians 
and jurists. Suggestive as these books are for disclosing 
different mental activities, they give no means of evalua- 
ting the disclosures. They show the puerile stage in di- 
agnosis which had been reached before standardized tests 
were available. 

Among those who are engaged in practical clinical work 
for determining mental development the Binet Scale has 
advocates who are quite as ardent as critics we have noted. 
Goddard, Kuhlmann (139), Wallin (213), and Towne 



CHECKING BINET DIAGNOSIS 175 

(201), have all used it in the practical examination of 
hundreds of cases and heartily commend its use in con- 
nection with delinquents, as does Healy for the earlier 
ages (27, p. 80). On the other hand there is a growing 
sentiment that the examinations should only be entrusted 
to experts in mental development. It is felt that the 
physician who has not had enough training in a psycholog- 
ical laboratory to understand the snares of mental tests, 
and very few have had this opportunity, ought to refer 
this question to a clinical psychologist as the best phys- 
icians now do when such experts are available. Perhaps 
nobody is so well equipped to judge a child's mental de- 
velopment without diagnostic tests as his school teacher, 
although Terman has shown that the teacher's judgment 
may be seriously at fault when he has not learned to 
dissociate mental capacity from the age and size of the 
child (196). In an editorial in the Journal of Criminology, 
Dr. Gault (106, p. 322) expresses the opinion that "dis- 
satisfaction with mental tests as a means of diagnosis' ' 
is traceable to the fact "that what the lay mind recog- 
nizes as palpable errors are often made by half-trained 
'investigators,' 'research directors' and even by men and 
women whose only qualification is that they have been 
trained for six weeks in a psychological clinic." Dr. 
Wallin demands that the tests should be used for diagnosis 
only by the psychologist with clinical experience. 

The American Psychological Association has cautioned 
against diagnosis by those inadequately trained and 
adopted the following resolution at its 1915 meeting: 

"Whereas, psychological diagnosis requires thorough 
technical training in all phases of mental testing, thorough 
acquaintance with the facts of mental development and 
with the various degrees of mental retardation. 

"And whereas, there is evident tendency to appoint for 
this work persons whose training in clinical psychology 
and acquaintance with genetic and educational psychol- 
ogy are inadequate: 



176 DEFICIENCY AND DELINQUENCY 

"Be it resolved, that this Association discourages the 
use of mental tests for practical psychological diagnosis 
by individuals psychologically unqualified for the work." 

Binet's suggestion as to the diagnosis of mental de- 
velopment seems to be best. He says that "the selection 
of defectives calls for three varieties of experience — that 
of teachers, of doctors, and of psychologists" {77, p. 38). 
These three points of view may be combined in a committee 
as in France, or the decision may rest with a specialist in 
mental development whose judgment should only be 
given after he has all the information which the medical, 
educational, and social diagnosis can provide to supple- 
ment his test records and his evaluation of the causes of 
the condition found. 

Those who are considering the legal isolation of the 
feeble-minded, especially defective delinquents, and sup- 
erintendents who wish a safe rule for transferring school 
children to special classes or schools for the mentally re- 
tarded should keep a committee plan in mind. A legal 
requirement embodying an examination by such a com- 
mission could easily be framed. In my opinion the ex- 
pert in mental development should be required at least 
to have the equivalent of a year of graduate work with 
his major time in testing. On the other hand very desir- 
able information as to children that require examination 
may be obtained by a teacher who uses a mental scale 
intelligently. In the hands of an amateur it may perform 
an analogous service to that of a vision chart in discover- 
ing children who require expert examination of their eyes. 
The danger lies in the novice not knowing his limitations. 
Few who have had experience with tests can doubt, how- 
ever, the much greater danger of inadequate diagnosis of 
mental development on the part of physicians who give 
opinions about mental deficiency without having had 
experience with test scales. 



CHAPTER VIII. SCHOOL RETARDATION 
AMONG DELINQUENTS 

A. In Minneapolis 

Besides the estimates of deficiency based on tests, the 
school records may furnish valuable objective evidence 
about mental retardation among delinquents. The school 
environment is the first prominent social environment to 
which the child must adjust himself. If he fails in this 
while in regular attendance we have an important in- 
dication of mental deficiency. With laws which require 
attendance at school, we may even estimate the mental 
character of groups, on the basis of success in school, 
provided that we use proper caution as to the effects of 
late entrance and of absence from school. Moreover, 
whether retardation in school shows mental deficiency 
or not, it certainly sets forth a vital problem in connection 
with delinquency. We shall first consider the school 
retardation of delinquents and leave the problem of check- 
ing the tests by school records until later. 

In order to study school retardation we tabulated the 
school position of 236 boys and 95 girls consecutively 
found delinquent in the Minneapolis juvenile court. To 
make the results more significant we did not include any 
cases dismissed at their hearing in court. Comparison 
with more serious delinquents is maide by means of the 
group of 100 juvenile repeaters and 123 from the Glen 
Lake Farm School. The school position and actual age 
of each delinquent was compared with the age and grade 
distribution among Minneapolis elementary school chil- 
dren. The latter was determined by a census made the 
same year the returns for which included about 15,000 of 

(177) 



178 



DEFICIENCY AND DELINQUENCY 



TABLE XII. 

Age and Grade Distribution in September of Pupils in the 
Elementary Schools of Minneapolis 

BOYS 





Ages 


Grades 


5 


6 


7 


8 


9 


10 


11 


12 


13 


14 


15 


16 


17 


18+ 


Totals 


I 


61 


1656 


629 


144 


44 


7 


4 


4 


4 




2 






1 


2556 


II 


1 


151 


979 


650 


221 


92 


28 


11 


4 


2 


1 








2140 


III 




12 


169 


724 


606 


290 


106 


44 


9 


10 


4 


3 




2 


2140 


IV 








140 


628 


635 


344 


184 


66 


34 


13 


2 






2046 


V 








2 


120 


489 


541 


371 


190 


88 


36 


9 


1 




1847 


VI 










5 


94 


428 


594 


380 


223 


96 


20 


1 


1 


1842 


VII 












7 


97 


422 


458 


397 


204 


60 


6 


2 


1635 


VIII 
















112 


308 


499 


346 


142 


27 


6 


1444 




62 


1819 


1777 


1650 


1624 


1614 


1552 


1742 


1419 


1235 


702 


236 


45 


12 


15489 



GIRLS 





Ages 


Grades 


5 


6 


7 


8 


9 


10 


11 


12 


13 


14 


15 


16 


17 


18+ 


Totals 


I 


45 


1642 


493 


117 


38 


9 


6 


3 




1 


1 






1 


2356 


II 




143 


890 


582 


159 


63 


27 


6 


5 


1 


1 








1877 


III 




10 


165 


755 


553 


193 


77 


27 


12 


4 










1796 


IV 






6 


168 


727 


618 


290 


132 


446 


18 


8 






1 


2014 


V 








12 


133 


573 


611 


309 


131 


44 


15 


4 




1 


1833 


VI 










7 


132 


493 


519 


330 


179 


80 


17 


1 


3 


1761 


VII 












6 


113 


447 


554 


342 


173 


29 


5 


2 


1671 


VIII 














6 


109 


432 


577 


348 


96 


12 


8 


1588 




45 


1795 


1554 


1634 


1617 


1594 


1623 


1552 


1510 


1166 


626 


146 


18 


16 


14896 



each sex (see Table XII).* The ages and grades were 
recorded for the beginning of September, when the school 
year opens, and the census was taken late in the year after 
all the children had been registered in school. That dif- 
ferent groups can only be properly compared when the 
age-grade distributions are made for the same time in the 
year is clear when one remembers that the ages are chang- 
ing throughout the school year while the grades remain 
the same for at least half the year. The census was taken 
for another purpose so that it unfortunately does not in- 

*The tables of Minneapolis school children were prepared by Mr. 
Andrew J. Lein and of delinquents by Miss Lydia B. Christ, to whom 
I am much indebted. 



SCHOOL RETARDATION AMONG DELINQUENTS 179 



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SCHOOL RETARDATION AMONG DELINQUENTS 181 

elude the high school pupils. Since the frequency and 
amount of retardation increases for older ages which oc- 
cur relatively more frequently in the groups of delinquents 
the comparison somewhat exaggerates the difference be- 
tween the groups. This difference in the relative ages of 
the groups is allowed for, however, in a later table on 
which the discussion will be based. The school positions 
of the various groups of delinquents and of ordinary school 
children are given in Table XIII and graphically in Figure 
2. 

In the Minneapolis group of elementary school children 
it will be found that there is about as much chance of a 
child being in either of the two most common ages for a 
grade. Among the boys, for example, 36% were in the series 
represented by age 6 in the first grade, 7 in the second 
grade, 8 in the third grade, etc., while 30% were in the 
series represented by one year older for each grade. It 
is, therefore, reasonable to regard either 6 or 7 as a satis- 
factory age in the first grade, 7 or 8 in the second, when 
one estimates the amount of retardation in this group. 
The allowance of two ages as satisfactory for a grade is 
in conformity with the practise of Strayer (189). The 
necessity of taking these ages at either the beginning or 
the end of the school year, and not merely "in the grade," 
is emphasized by the report of the New York City Com- 
mittee on School Inquiry (72). Ayres (71) also considers 
only those pupils over-age who are over 7 in the first grade, 
8 in the second, etc., so that this may be regarded as 
fairly well established as a standard for measuring the 
retardation in school position of groups of children. 

The summary of results in Table XIII shows that 70% 
of the ordinary delinquent boys were retarded in school 
position as compared with 27% among the Minneapolis 
boys in the elementary schools, 91% of the ordinary de- 



182 DEFICIENCY AND DELINQUENCY 

linquent girls as compared with 23% of the Minneapolis 
girls of these schools. When one compares the age dis- 
tribution of the delinquent groups, given in Table XIII 
with that of the Minneapolis school children in Table XII, 
it is clear that an allowance should be made for the much 
larger proportion of older children in the delinquent 
groups. This may be done by determining the percentage 
retarded at each age and in each group and then calcu- 
lating indices of retardation by weighting the percentage 
retarded at each age in the proportion to the number of 
delinquents at that age. Table XIV gives these results 
for the ages 8 to 15 inclusive. 

For example, in calculating the indices 39 and 70 for 
the frequency of retardation among ordinary delinquent 
boys as compared with elementary school boys, the per- 
centages retarded at each life-age for each of these groups 
was multiplied by the number of ordinary delinquent 
boys at this age, as shown lower in the table, and the totals 
divided by the number of ordinary delinquents, 213. 
The average frequency of the retardation of a school 
group which compares in ages with the delinquent group 
was thus determined. In calculating the indices of amount 
of retardation the same procedure is followed except that 
the average number of years retarded is found for each 
age and this is multiplied by the number of delinquents 
at that age. The 16-year-olds are omitted because of 
the inadequacy of the school census for this age. Ac- 
cording to the standard which regards 7 years as satis- 
factory in the first grade there can be no retardation under 
eight years of age. Since some of the pupils 13 years of 
age and over have reached high school and so do not 
show in the Minneapolis table the percentage of retarda- 
tion for children 13-15 years is based on the assumption 
that the number of children at these ages will be the same 
as the average number for 11 and 12 years. No credit 
could be allowed for those advanced in school positions 
on account of the incompleteness of the Minneapolis 
census for older ages. The comparison is, therefore, on 
the basis of retardation alone. 



SCHOOL RETARDATION AMONG DELINQUENTS 183 



TABLE XIV. 

Indices of Frequency and Amount of School Retardation of 
Minneapolis Juvenile Delinquents Compared with 
Minneapolis School Children of Cor- 
responding Ages. 

(Age 7 or younger regarded as satisfactory in the first grade.) 





retardation 




Percentage Retarded at Each Life-Age 


School Boys 
Delinquent Boys 
School Boys 
Glen Lake Boys 
School Girls 
Delinquent Girls 


Index 

39% 
70% 
36% 
86% 
35% 
90% 


8 
8 


7 



9 
16 

44 

17 

12 

100 


10 

24 
50 

50 
16 
50 


11 
31 
67 

46 
25 

50 


12 
35 
58 

66 
31 
75 


13 

40 
60 

81 
33 

83 


14 

45 
77 

61 
37 
95 


15 

43 
93 

87 
93 
100 




Index 


Average Amount of Retardation in Years 




School Boys 
Delinquent Boys 
School Boys 
Glen Lake Boys 
School Girls 
Delinquent Girls 


.61 Yr. 
1.27 Yr. 

.54 Yr. 
1.54 Yr. 

.64 Yr. 
2.29 Yr. 


.09 
.00 

.07 
.00 


.19 
.66 

.17 

.15 

1.00 


.31 
.50 

.50 

.22 

1.00 


.43 
.86 

.62 

.34 

1.00 


.54 
1.09 

1.25 

.45 

1.25 


.63 
1.11 

1.86 

.50 

2.25 


.78 
1.23 

2.11 

.59 

2.05 


.64 
2.11 

2.03 

.82 

2.84 




Totals 


! Number of Children at Each Life- Age 




School Boys 
Delinquent Boys 
Glen Lake Boys 
School Girls 
Delinquent Girls 


13,123 
213 
108 

12,781 
82 


1650 
3 


1634 
2 


1624 
9 
6 

1617 

1 


1614 
6 
8 

1594 
2 


1552 
21 
13 

1623 
2 


1742 
25 
12 

1552 

4 


1647 
47 
21 

1587 
12 


1647 
56 
18 

1587 
21 


1647 
46 
30 

1587 
338 



Index equals the sum of retardation at each age multiplied by the number of delin- 
quents at that age divided by the total number of delinquents. 

From the indices of frequency of retardation in Table 
XIV it will be seen that retardation of one or more years 
below the standard of age 7 in the first grade is nearly 
twice as common among the ordinary delinquent boys as 
among a group of school boys of corresponding ages, while 
it is fully 2y 2 times as great among the ordinary girl de- 
linquents as among a corresponding group of school girls, 
when estimated on the same basis. 

To understand the significance of this comparison one 
should consider the relative difference which is shown 
between school children and delinquents in the statistics 
of health, defective sight, nose and throat obstructions, 
etc. The percentages of consecutive delinquents show- 



184 DEFICIENCY AND DELINQUENCY 

ing other defective or diseased conditions has never, so 
far as the writer is aware, been found to be double that 
among the school children generally when figured on a cor- 
responding basis. Medical inspection shows that for 
other conditions than retardation the frequency of defects 
and disease found among representative groups of ordin- 
ary juvenile delinquents can often be equaled in the poorer 
schools of the city. To find a factor relatively twice as 
common among delinquents as among school children, 
when the frequencies are as great as with retardation, 
means a variation that is unquestionably significant. 
This is, of course, not an argument against the detection 
and treatment of handicaps that can be benefited by the 
physician. It only suggests the relative size of the two 
problems. 

In considering the frequency of school retardation 
among delinquents in Minneapolis, it will be noted that 
the most serious condition is clearly among the girls, 90% 
of whom are below grade as compared with the index of 
35% for the corresponding group of school girls. 

One may estimate that the chance of a Minneapolis 
boy who is retarded in school getting into juvenile court 
is about Zy 2 times that of a boy who is up-to-grade. But 
the chance of a girl who is retarded in school getting into 
juvenile court is about 17 times as great as that of a girl 
who is up to grade. This calculation is easily made 
on the assumption that the indices of Table XIV are 
typical for a single year, knowing that about 194 in 
10,000 school boys in Minneapolis get into the court 
annually and 21 in 10,000 school girls. 

The best measure of the difference in school attainment 
cannot be shown, however, without considering the 
amounts instead of the frequency of retardation in the 
groups compared. We should regard two years retard- 



SCHOOL RETARDATION AMONG DELINQUENTS 185 

ation as twice as serious as one year and make a corres- 
ponding allowance for each additonal year of retardation. 
Thus weighting our results we find in the indices of Table 
XIV that the boys 8-15 years of age in the Glen Lake 
Farm School group of delinquents have on the average 
lost 1.54 of a year through retardation in school attain- 
ment compared with the satisfactory standard of 7 in 
the first grade. The ordinary delinquent boys have 
lost on the average 1.27 of a year, while the indices for 
Minneapolis school boys of corresponding ages are — .54 and 
— .61 of a year respectively. Among the ordinary de- 
linquent girls the average amount of retardation on the 
same basis is 2.29 years as compared with .64 of a year 
among the school girls of corresponding age distribution. 
The indices for the amount of school retardation are 
the most significant figures in any of these tables, although 
they are based on too few numbers to afford more than 
rough comparisons. It is, however, a fairly reliable 
estimate to say that retardation in school attainment in 
Minneapolis is about twice as great among ordinary de- 
linquent boys and among the detention home group while 
it is three times as great among ordinary delinquent girls 
as among corresponding groups of elementary school chil- 
dren. If we had been able to credit the groups with those 
in advance of the expected position for their ages the dif- 
ference would have been even greater. 

B. School Retardations Among Other Groups 
of Delinquents 

In view of the fact that retardation in school offers an 
important check upon the question of the frequency of 
mental deficiency among groups, besides stating a differ- 
ent training problem of its own, it is curious that it has 
not been more systematically studied in connection with 



186 DEFICIENXY AND DELINQUENCY 

delinquency. Few investigations include any reference 
to the question. Auden [69] reports that among 263 
committed to Borstal institutions (juvenile reformatories) 
in England for the year ending March 31, 1909, 71% (186) 
had not reached the fourth standard, corresponding to 
the fourth school grade. These were delinquents be- 
tween 16 and 21 years of age. The next year 402 out of 
554 (72%) had hot reached the fourth grade. Not one 
person had reached the eighth grade and only 13 the 
seventh grade. In the Minneapolis detention home group 
only 23 out of the 103 over ten years of age were below 
the fourth grade. 

Cornell gives the distribution of 236 boys in special dis- 
ciplinary classes of two Philadelphia schools [93). These 
classes are for truant and difficult boys 8 to 14 years of 
age inclusive. While they are not technically delinquents 
the problem is similar and they show even more serious 
school retardation than the Minneapolis group. Sum- 
marizing his results according to the standard which 
counts ages six or seven as satisf acton* in the first grade, 
and so on, we find 12.3% satisfactory ; 12.3% retarded 
one year; 26.7% retarded two years; 30.1% retarded 
three years; 15.8% retarded four years; 2.5% retarded 
5 years; and 0.4% retarded 6 years. Eighty-eight per 
cent are thus behind a satisfactory position in the grades, 
and 48.8% three or more years behind. This is to be 
compared with 70 and 16% among ordinary Minneapolis 
delinquent boys (Table XIII). 

Among 647 prostitutes at the Bedford (N. Y.) Reforma- 
tory 48% either could not read or write any language or 
had not finished the primary grades. Seven per cent, had 
graduated from the grammar grades. Among 610 pros- 
titutes in other reformatories reported in the same work, 
only 23% had finished the fifth grade. Among 877 street 



SCHOOL RETARDATION AMONG DELINQUENTS 187 

cases from which information was obtained 814 had no 
more education than ability to read and write, 53 had 
graduated from the grammar grades or had some special 
education (133). Another report by Weidensall we shall 
consider in the next chapter. 

The attending physician (60) of the Morals Court in 
Chicago inquired "of as many of the defendents as she 
could, who were charged with being public prostitutes, 
as to what ages they had left school/ ' Among 3546 cases 
which passed before the court in seven months the report 
covers 494 cases. Of these only 17 had gone beyond the fifth 
grade in school, only one was a high school graduate (161). 
Among 100 girls at the Ohio Industrial School, 11 to 18 
years of age, median age 15 years, 50% were in the third 
or fourth grade and 54% had failed of promotion three 
or more times (55). 

Drucker gives the age-grade distribution of 100 random- 
ly selected minor offenders, 15 to 22 years of age, in the 
Cook County (111.) jail. This shows that 41 of these were 
below the eighth grade and three or more years retarded 
at the age they left school. They might well be examined 
for deficiency. Among 86 who left school at 14 or after, 
24 were in the fifth grade or below (101). Among 100 
consecutive admissions to the Ohio State Girls Industrial 
Home, Renz reports 25% in the third grade and 25% in 
the fourth grade, 15% in the fifth grade; 29% failed of 
promotion 4.5 to 6 years and 25% more failed of promo- 
tion 3 years (47). Storer reports on the same groups 
(55). Bluemel finds that 100 probationers in the Denver 
Juvenile Court were retarded in school 2 years on the 
average as compared with an average school retardation 
among the school boys of Denver of 1 year (2). At the 
New Jersey State Home for Girls among a group of 163 
selected cases 102 had not reached the fifth grade although 
their average age was 17 (12). 



188 DEFICIENCY AND DELINQUENCY 

The school distributions by age is given for 215 delin- 
quents in the California State School at Whittier for boys 
by Williams (62) in sufficient detail to make it usable for 
estimating the frequency of deficiency on a plan we shall 
consider shortly. Regarding age seven as satisfactory for 
the first grade, and so on, only 7 of these boys had reached 
this standard. Supposing that those older should have 
attained at least the grade which is satisfactory for the 
14-year-old, and those younger the corresponding grades, 
we find that 29 c 7 were four or more years below this 
standard and 14^ were five years below this standard. 
In the next section we shall endeavor to find out how the 
school records might also be used as symptomatic of 
mental capacity. 



CHAPTER IX. COMPARISON OF THE SCHOOL 
TEST AND THE BINET TEST 

There has been considerable discussion of the question 
whether psychological testing should be expected to con- 
form to the ranking of pupils in school. This discussion 
however, does not attack the question in which we are 
especially interested, L e., how to get the best information 
from both. If the school level were measured by the 
progress made in school by passable work and not by the 
school position attained often merely through age or size, 
Binet would be right in expecting that in general they 
would correspond among groups of children in the public 
schools. Agreement with real school progress could, 
therefore, be taken as a criterion of a good series of tests, 
as it has been by Binet and Bobertag. On the other hand 
Meumann and Abelson were right in objecting to the 
proof of the value of tests by agreement with the school 
level, if they limited their objection to tests applied to 
exceptional children and to using school position as a 
final test of school level. Lack of correspondence with 
our group of delinquents is, of course, no indication of a 
weakness in the Binet scale. In numerous instances 
they had been promoted in school because of age without 
doing passable work. The reader should also see the 
evidence of the teacher's bad judgment of a pupil's abil- 
ity assembled by Terman and by Terman and Knol- 
len (196). 

Terman has calculated the correlation between intel- 
ligence quotients determined by the Binet scale and the 
teacher's estimates of scholastic or of general ability. 
These gave coefficients of .48 and .45. Doll has found 
for Goddard's data on school children that the correla- 
tion of school grades is closer with life-age than with test- 

(189) 



190 DEFICIENCY AND DELINQUENCY 

age, .84 as compared with .73 (12). This indicates an 
influence of life-age upon promotion. In a school for 
deficients Burt found the correlation of teachers' esti- 
mates with Binet ages was .55, with mental retardation 
or excess .59, with intellectual quotient .48. He quotes 
Mclntyre and Rogers as finding coefficients about .5 for 
similar calculations with normal school children in Scot- 
land (85). Starch has shown that measured by the com- 
bined ability in reading, writing and spelling a third of 
the pupils are in a grade behind and a third are in a 
grade ahead of their ability (186). 

However much we might disagree as to how close a 
correlation might be expected between the Binet tests 
and school level, independent of the relation to life-ages, 
or which is the better test, it is certain that they afford 
two different symptoms of mental deficiency. It be- 
comes our immediate problem, therefore, to discover how 
the most information may be gained from a careful inter- 
pretation of the test of school level. If we had sufficient 
data, three sorts of checks might be formulated. 1. 
What amount of school retardation will give us the best 
estimate of mental deficiency among groups? 2. What 
amount of school retardation should put an individual's 
mentality in question so that he should be examined? 
3. What amount of school success should put in question 
a Binet diagnosis? 

A. Practical Uses of the School Test. 

(a) ESTIMATING THE FREQUENCY OF DEFICIENCY 
BY SCHOOL RETARDATION. 

We shall first take up the question of utilizing informa- 
tion about school retardation in estimating the frequency 
of mental deficiency among groups of delinquents. It is 



SCHOOL TEST AND BINET TEST 191 

perfectly clear that retardation in school position is not 
always an indication of mental retardation. A child 
may be behind the position in school reached by the chil- 
dren of his age merely because he has not attended school 
so long as his companions. A census of school progress 
which we took in Minnesota indicates that in general a 
large part, perhaps half, of the retardation in school is to 
be thus explained even under compulsory attendance 
laws. Some allowance is also to be made for physical 
handicaps, such as defects of sight and hearing which 
are not corrected, illness which does not cause prolonged 
absence, frequent change of schools, bad home conditions, 
etc. Aside from absence, however, there can be no 
question that greater or less degrees of mental retarda- 
tion is the main cause of retardation in school. Moreover 
a dull mind is often the reason for beginning school at an 
older age and for staying away from an unsuitable school 
environment as much as the law will permit. In any par- 
ticular case, it is to be noted, however, that all of the ex- 
cuses for backwardness in school are not likely to account 
for more than one or two years of lagging for other reas- 
ons than dullness. 

We cannot hope at present to get nearly so accurate a 
judgment about the frequency of deficiency in groups by 
means of any school test as by the psychological tests. 
Nevertheless, I believe that it may furnish us some sup- 
plementary evidence. The main difficulty in formulating 
any general rule for interpretation of the school level is 
that very different plans of promotion prevail in different 
school systems. It is not uncommon, for example, to 
find that a child will be promoted to a higher grade re- 
gardless of his ability provided that he has spent two 
years with the same teacher. This practise, of course, 
makes it impossible to judge a particular individual's 



192 DEFICIENCY AND DELINQUENCY 

ability by the school grade he has attained without know- 
ing how he reached it. Nevertheless, spending two years 
in each grade will begin to show in a general distribution 
of pupils by the time we deal with 12-year-olds. I have 
gone over the tables of school retardation of pupils pro- 
vided by Strayer for several hundred cities in the United 
States and I find that the percentage method of approach 
gives us at least a rough cue as to what might be expected 
by any general principle of interpretation (189). 

Using age 7 as satisfactory in the first grade, 8 in the 
second, and so on, we find that among 319 cities of all 
sizes, half of them had 2% or more retarded four or more 
years in school position. This condition was about the 
same for cities less than 25,000 as with the larger cities. 
On the basis of school position for groups of children of all 
the school ages it would, therefore, be safer to make a 
low estimate of the frequency of mental deficiency on 
the basis of five or more years of scholastic retardation 
in the groups and regard 4 years or more of school re- 
tardation as a maximum estimate. Since most children 
leave school at 14 it is generally best to regard all older 
as only 14 years of age when estimating deficiency. I 
have not been able to check this by school and test records 
on a group of children through all the grades. Goddard's 
published records do not give the mental ages for those 
four or more years retarded scholastically. Moreover, 
he only included those in the sixth grade and below. For a 
group of young children this estimate would undoubtedly 
be too low. The delinquent groups, however, are all older. 
Most of them, if they lived in this country have gone to 
school until they were at least 14 years of age. Wallin 
(211) and Strong (190) also give records of school position 
to check the Binet rating. 

By considering only pupils in the public schools who 
are 12 and 13 years of age, the last years in which prac- 



SCHOOL TEST AND BINET TEST 



193 



TABLE XV. 

Percentages of Pupils 12 and 13 Years of Age Most Seriously 
Retarded in School 





Percentages Retarded 




4 or more grades 


5 or more grades 


Cincinnati, Ohio — June 1907 


8.8% 


2.5% 


Cleveland, Ohio— 1909-1910 


3.0 


0.9 


Des Moines, Iowa — 1915 


1.0 


0.2 


Memphis, Term. — June 1908 


6.6 


1.5 


Minneapolis, Minn. — June 1915 


1.3 


0.5 


Pittsburgh, Pa.— 1913 


4.7 


1.1 


Springfield, Mass. — Sept. 1907 


1.2 


0.1 


Reading, Pa.— 1906-1909 


2.2 


0.4 



The distributions for Cincinnati, Memphis and Springfield are taken 
from Ayres' Laggards in Our Schools. That for Minneapolis is from 
unpublished data. That for Reading is from Snyder's Retardation 
in Reading Public Schools. The others are from Superintendents' re- 
ports. 

tically all are in school, we can get a check upon this 
method of estimating for delinquent groups. I have 
compared the age-grade distributions for those of these 
ages in eight cities showing the percentages retarded 4 or 
more and 5 or more years. They are given in Table XV. 
These records indicate that at least five or more years 
retardation below a standard of age 7 in the first grade 
for all who are 12 years of age or over might be taken for 
a low estimate of the frequency of deficiency, and four or 
more years retardation for a maximum estimate. Except 
under special circumstances those who are older than 14 
years should be considered as if the highest grade attained 
was at 14 years of age. These borderlines of school re- 
tardation for the purpose of estimating the frequency of 
deficiency check fairly well with estimates for the Min- 
neapolis and other groups of delinquents which have been 
tested by the Binet scale, as we shall note later in this 
chapter. 



194 DEFICIENCY AND DELINQUENCY 

In order that the school test of mental deficiency should 
be as good as the Binet system it would have to provide 
a standard of school progress relative to length of attend- 
ance instead of school position relative to age. If one 
could say that a child was not above the lowest 0.5°^ of 
the children of his age in the progress which he had made 
in school relative to the time actually spent in school, 
one would then have an excellent standard for judging 
feeble-mindedness for any child who had been in school 
for some years. It would be better if an uncertain region 
were also defined. By the time that a child's ability has 
been passed upon for four or five years and by different 
teachers, even from the point of view of the needs of school 
work, one has a criterion for mental ability in a particular 
community applied under long observation, which no 
system of brief tests can hope to equal for some time to 
come. Such a standard, however, is unfortunately not 
available since we have too little information about school 
progress relative to attendance. Even if it were available, 
psychological tests would still be an important check 
upon the school judgment on account of the excessive 
value put upon mere memorizing in school and on account 
of the emotional repulsion to the school developed by 
some children of ability. Mental tests would be necessary, 
moreover, for the younger ages. 

b SCHOOL RETARDATION AS A WARNING OF THE 
NEED FOR EXAMINATION. 

Even if no more is known than a person's grade in 
school at any age over eleven it is an important cue as to 
his mentality. Here our problem is not estimating de- 
ficiency among groups but the discover}' of deficient in- 
dividuals. We wish to find the highest grade in school 
in which we are at all likely to find children under present 



SCHOOL TEST AND BINET TEST 195 

conditions who test in the lowest 1.5% for their ages. 
Our records on 653 15-year-olds indicate that a pupil of 
this age who tests doubtful is very rarely retarded less 
than 3 years in school. It occurred only twice when tested 
ability was judged by the 1911 tests, four times judged by 
the 1908 scale. None of the 15-year-olds who tested 
presumably deficient were retarded less than three years. 
In Minneapolis, as in many cities, the custom prevails 
of promoting, regardless of passable work, after two years 
have been spent in a grade. 

We suggest, therefore, to be perfectly safe, it is well for 
every child in court to be examined who is two years re- 
tarded in school below the standard age of 7 in the first 
grade and is not able to carry work above the seventh 
grade. This will include a considerable number of chil- 
dren at the lower border of those presumably passable. 

Binet used this standard of two years retardation in 
recommending examination for children 9 years of age or 
over (3 years below age 6 in the first grade) (77, p. 44). 
He adopted it from Belgium. It is also quite commonly 
followed in this country. The New Jersey law provides 
for special classes in any school district where there are 
ten or more children four or more years behind grade. 
This probably means behind the theoretical position of 
age 6 in the first grade, one year worse retarded than we 
suggest examining. Goddard says in one place that "a 
child who has been in school regularly and is two or three 
years behind his grade is so suspicious that it is almost 
certain that he is feeble-minded" (116). But later he is 
much more conservative and says, 'The child who is 
fourteen years old and cannot pass an examination in 
fourth grade work is almost surely feeble-minded' ' (34). 
As judged by Stray ers' tables the suggestion that examina- 
tion is desirable for those two years behind a standard of 



196 DEFICIENCY AND DELINQUENCY 

age 7 in the first grade would tend to bring in for exam- 
ination about 18% of the school boys in half of the cities 
of 25,000 population and over. This would not be too 
severe a burden for courts which would be interested only 
in that portion of these retardates who were brought into 
court. 

This school test may be made of decidedly practical use 
by those working in juvenile courts where most of the 
cases are with children over this age. It can be applied 
in a very simple manner by subtracting 8 from the child's 
age and only passing without testing those who are in a 
grade in school higher than the number remaining. For 
example, if the child is 13 years of age, subtracting 8 gives 
5. Now, if the child is in the fifth grade or lower, or 
entered such a grade at the time he was of this age, one 
should investigate the question of feeble-mindedness. 
Unless more than one year of the retardation is explained 
by the person's absence from school since he was six 
years of age, he should always be turned over to an ex- 
pert for examination. This retardation of two years in 
school attainment below the standard of seven in the first 
grade may indicate feeble-mindedness if the child has 
been attending school constantly, although the chances 
are perhaps 6 to 1 that it does not. It is very desirable 
that we should have more adequate data on this point. 
A cautious court, however, would inquire into the mental 
ability of any child — at least two years retarded in school, 
L e., any child the number of whose school grade is not 
higher than the remainder after subtracting 8 from his 
life-age at the time that he entered his last grade or who 
is not actually carrying the school work of an advanced 
grade. This latter caution we must now consider. 



SCHOOL TEST AND BINET TEST 197 

(C) SCHOOL SUCCESS AS A CHECK ON THE BINET 
DIAGNOSIS. 

The school test can give us still another practical cue 
as to feeble-mindedness in examining children. Ability 
to carry successfully school work of some grade certainly 
could be used as a systematic criterion of passable in- 
tellectual ability. What school grade indicates this is 
not at present possible to determine except as a rough 
practical check. With the great irregularity in school 
grading at present known to exist, it certainly would not 
be possible to say that fifth grade work indicates a pas- 
sable intellect, although some of the oldest local schools 
for deficients, like those in Mannheim, do not pretend to 
carry children above the fourth grade work. Speaking 
of the school success of the intellectually deficient, Binet 
said: ."One may draw the conclusion, which is of practical 
value, that one need not seek children of this group in the 
senior divisions of the primary schools" (77, p. 44). This 
would correspond to the sixth and seventh grades in this 
country. Tredgold gives a careful description of the 
highest work in a London special day-school for the high- 
est grades of deficients. It shows that even fifth grade 
work would be beyond what is actually taught the chil- 
dren in this school. He says: 

"The work done by this class consists of reading and 
writing, equivalent to normal Standard II; compound 
addition and subtraction up to 1000, and simple multi- 
plication and division. Excluding a few children — who, 
in my opinion, are not really defective — it may be said 
that the scholastic acquirements of none of these chil- 
dren come up to the Standard II. In occupations and 
manual work they are decidedly better, and a consider- 
able portion of the children of this class can cut out and 
make simple artificial flowers, knit rugs and weave bas- 
kets, with a really very creditable amount of dexterity, 



198 DEFICIENCY AND DELINQUENCY 

which redounds in no small measure to the patient, 
persevering and systematic care of their teacher' ' (14, 
p. 173). 

Some of our group with doubtful intellects do better 
than this. When considering the borderlines with the 
Binet tests we decided that a child was presumably pas- 
sable if he scored a test-age of XI. This score would not 
be made by 11-year-olds as a group, but could probably be 
attained by 12-year-olds. We may then ask what is the 
corresponding school position attained by 12-year-olds 
who have been continuously in school. At the same time 
we must ask whether the lowest 1.5% of the children of 
any single age can attain this school grade since it should 
be high enough to exclude the deficients, no matter 
how long they have attended school. We happen to 
have this information for a random group of Minneapolis 
elementary school pupils on the basis of census of school 
progress per years of schooling. Considering only the chil- 
dren who had been in school since they were six years of 
age, we found that 82% of 186 12-year-olds and 92% of 174 
13-year-olds had reached the seventh grade, and that the 
lowest 1.5% of neither age nor of any of the older ages 
could apparently carry the work of this grade no matter 
how long they had remained in school. Our records in- 
cluded older pupils who were in their eleventh year of 
attendance on the elementary schools. 

Another indication that reaching the seventh grade is 
presumptive evidence of passable intellects is found in 
the fact that none of our group of 653 15-year-olds testing 
presumably deficient with the Binet scale and only four 
of the six who tested doubtful intellectually had reached 
the seventh grade. On the other hand those that think 
that a 15-year-old testing XI is deficient will be interested 
to find that 42 out of 51 who tested XI with the 1908 scale 



SCHOOL TEST AND BINET TEST 199 

were in the seventh grade or above. We are convinced, 
therefore, that it is a conservative position to take that 
either passing the Binet tests XI in the 1908 series or 
ability to pass successfully the seventh grade in school is 
good evidence of a passable intellect. The rule, of course, 
does not apply to those who are passed along to the sev- 
enth grade because of their size or age regardless of ability 
to carry the work. 

B. Checking Deficiency Among Delinquents 
by the School Test. 

Let us see what the rough preliminary estimates on the 
basis of school retardation would indicate for the Minne- 
apolis delinquents. We may disregard the upper limit 
of 14 years since compulsory attendance in Minnesota for 
backward pupils continues until age 16. For the limits 
of five and four years of retardation in school below the 
standard of 7 years in the first grade we would have esti- 
mates of 2.6% to 6% of deficiency among the ordinary 
cases of delinquent boys and 14.7% to 23.1% among the 
ordinary delinquent girls. Among the recidivist group of 
boy offenders 3% to 11% would be below these border- 
lines. Among the Glen Lake School group 12% are four 
years or more and 4% five years or more retarded. This 
last is to be compared with our judgment on the basis of 
individual examinations with the Binet scale in which we 
concluded that 2% were presumably deficient and 5% 
doubtful as to deficiency. The estimates on the basis of 
school retardation are somewhat too large. This would 
certainly be true for older delinquents. In as much as 
the laws for compulsory school attendance usually do 
not enforce attendance after 14 years of age, it would 
probably be better generally to treat all over 14 years of 
age as if they were of this age at the time of leaving school. 



200 DEFICIENCY AND DELINQUENCY 

This limiting age of 14 checks more closely with the mental 
examination records reported by Williams (149) and 
Ordahl (41) for groups of delinquents in the California 
state schools. 

With her unselected group of 88 women at the Bedford 
reformatory, Weidensall found that 39% had not com- 
pleted the fifth B grade (60, p. 23). This is not far from 
the estimate of presumable deficiency among such in- 
mates on our borderline with the Binet scale. Consider- 
ing the actual years of school retardation relative to years 
of attendance, so far as she was able to discover, and add- 
ing the 8 who never attended school, we have 20% five 
or more years retarded in school and 28% four or more 
years retarded (60, p. 251). She says further regarding 
the bi-modal distribution of ability which she found among 
her group: 

"The division which alone served to separate the better 
from the poorer subjects was that of the grade complet- 
ed upon leaving school. Those who had accomplished 
the completion of at least 5B grade formed a curve which 
paralleled very closely that of the Cincinnati girl of fif- 
teen, while those who had not succeeded in passing 5B 
comprised the majority of those who collected at the 
poorer mode of the Bedford 88 curves. Throughout, the 
grade completed has proved to be more often a measure 
of our subjects' ability to progress in school, less often a 
measure of their opportunity to attend school/ ' 

The administrative officers of institutions may make 
rough estimates of the frequency of serious deficiency 
among their charges by regarding all over 14 as if they 
were 14 years of age or under, disregarding those under 
12 years of age, tabulating the highest school positions 
reached, and finding the frequency of those four or more 
and five or more grades retarded below a standard of 
age 7 for the first grade. It would be well for each court 



SCHOOL TEST AND BINET TEST 201 

also thus to make an estimate of the size of the problem 
of deficiency in its jurisdiction. According to the second 
suggestion which we have made, the Minneapolis Juv- 
enile Court, for example, should plan to examine for men- 
tal deficiency all those two or more years retarded in 
school or about 20% of the boys found delinquent and 
nearly half of the girls. The prospect would be that the 
number sifted out as having feeble intellects will be less 
than 10% of the ordinary run of cases. 

Let us study a little further into the detention home 
cases tested by the Binet scale and see what additional 
light their school position throws upon the question 
whether or not they are defective delinquents. Four 
years' retardation in school position would have called 
attention to both of our sure cases of feeble-mindedness. 
On the other hand, it would have brought in for exam- 
ination only 4 out of the 7 doubtful cases. Three years 
of school retardation would have sifted out all but one. 
Two years school retardation, the rule suggested above, 
would have detected all those who tested doubtful. It 
would have required 56 examinations in this group to 
have found the eight cases suspicious under our test cri- 
teria. We also find that, among the random 15-year-olds 
not delinquent, examining all those 3 years retarded 
would have discovered all that tested even doubtful in- 
tellectually. 

Applying the rule that ability to carry seventh grade 
work is a good indication of a passable intellect, we find 
that none of our Glen Lake delinquents testing either 
presumably deficient or doubtful had reached the seventh 
grade. On the other hand, if one were disposed to object 
to saying that a person who passes Binet tests XI (1908) 
has a passable intellect, one finds in reply that 16 out of 
the 22 Glen Lake delinquent cases testing XI and three 
or more years retarded intellectually, i. e., presumably 
passable, were carrying seventh grade work or better. 



202 DEFICIENCY AND DELINQUENCY 

In examining individuals the importance of checking 
each of these tests with the other seems perfectly clear. 
If a boy fails in the Binet tests and shows better school 
ability one should certainly be cautious in his diagnosis. 
On the other hand a boy who is seriously behind in school 
may be found by the Binet scale to have a better intellect, 
so that the inquiry must be further extended to determine 
the cause of his school retardation. Retardation in school 
is generally not as fundamental a symptom of deficiency 
as retardation in the tests because of the numerous other 
causes of delay in school. 

After allowance for the external causes of backward- 
ness in school one finds that the test of progress in school 
and the Binet examination not rarely reach two different 
sides of the nature of unusual children found in juvenile 
court. Working with these exceptional children, Dr. 
Kramer observed that school performances were often 
notably different from ability in the tests. After check- 
ing the two tests against each other in examining 59 cases 
sent to him from the Society for the Care of Delinquent 
and Dependent Children in Breslau and 59 children at 
the psychiatric clinic in Berlin, he says regarding the 
result of this comparison: 

'Tor the valuation of the Binet method, it shows us 
that the first objection which occurs to one, that the 
method tests only school knowledge, is not correct. On 
the contrary it was found that we had to do in high de- 
gree with that which was independent of what the child 
had learned in school and with real abilities which the 
normal child is accustomed to acquire by a certain age 
uninfluenced by training and instruction/ ' 

He emphasizes, however, that to answer practical 
questions regarding the training of a child, "we must 
not only examine into the understanding but the total 
personality must be taken into consideration' ' (184, p. 519). 



CHAPTER X. BAD SCHOOL ADJUSTMENT 
AS A CAUSE OF DELINQUENCY 

The comparison of the Binet and school tests for our 
group of serious delinquents suggests another important 
comparison. Many delinquents are found to be appar- 
ently wrongly placed in school relative to their intellectual 
development. They form a group for which not isolation 
but training is needed, a group notably larger than that 
which should be sent to institutions for the feeble-minded. 
This bad adjustment of juvenile delinquents to their 
school work is not the same problem as backwardness 
in school. It means attendance in school classes unsuited 
to the child's mental ability. In a paper before the 
Minnesota Annual Conference of Charities and Correc- 
tions in 1910, I briefly forecasted this problem (152). It 
is now clearly indicated by the records of the group of 
delinquents at the Glen Lake Farm Training School. 
This comparison is made in Table XVI. 

In order to be thoroughly conservative in estimating 
this problem of maladjustment to school work, let us 
not only allow for two mental ages to be satisfactory for 
each grade, as indicated in the table, but in addition omit 
all cases which might be credited with an intellectual de- 
velopment above XII. This eliminates the objection 
to considering higher age tests, for nobody questions 
that tests XII or above indicate at least a 12-year-old 
intellect. After these extremely liberal allowances we 
still find 54 of the 104 boys in the detention home testing 
less than XIII who were in school grades the work of 
which was presumably not suited to their intellectual 
level. Seventeen of the boys (16%) were at least two 
years out of adjustment to their school work. If we dis- 

(203) 



204 



DEFICIENCY AND DELINQUENCY 



TABLE XVI. 

School Positions of Delinquents at Glen Lake Relative to 

Their Intellectual Development 



School position worse 


Alike* 


Better 


Total 


3 yr. 


2 yr. | 1 yr. 




29 


1 yr. 
16 


2yr. 
4 


3yr. 
2 


4 yr. 
2 




1 


8 21 


21 


104 



*Mental ages VI and VII regarded as satisfactory for the first grade, 
etc. 

regard those who were trying to carry work too difficult 
for their capacity because placed a year or more ahead of 
their ability, we find 30 out of adjustment because at 
least one grade behind the class suited to their intellects. 
Over a quarter of our detention-home group was thus 
placed in school a year or more below grades attended 
by the pupils of corresponding intellectual development. 
It may be said that some of those behind their proper 
intellectual position in school may have been kept back 
because of instability, laziness, or other volitional char- 
acteristics which might fail to show in tests of intellectual 
performance. This is probably rare, and, when found, 
it often means merely that the pupil requires more at- 
tention to secure results. 

That our delinquents are not unique in their malad- 
justment to school as judged by their tested abilities, is 
indicated by the report of Ordahl on the school position 
of the special group of 341 delinquents in the state school 
at St. Charles, California. The median of their school 
positions, counting seven years as satisfactory for the 
first grade, fell a grade and a half below that which their 
tested mental development seemed to justify. He notes 
that "mentality is not alone responsible' ' for their low 
grades in school. Moreover, he believes that it shows 
the necessity for a more objective pedagogical method in 
dealing with them (41, p. 81). 



BAD SCHOOL ADJUSTMENT AND DELINQUENCY 205 

Only a prolonged trial of special instruction for those 
presumably behind their proper grade would finally de- 
termine how large is this evil of maladjustment. Such 
an experiment could be satisfactorily carried out only 
with the co-operation of the board of education. It 
would mean the employment for some years of expert 
teachers to train those delinquents found behind their 
.intellectual level in school. Until that time we shall 
have to take the estimate from psychological tests which 
indicated that, in our group of serious juvenile delin 
quents, presumably 29% of those compared had been 
held back by the school machinery. Since the retarda- 
tion of these pupils may be attributed to a late start in 
school life or prolonged absence, the inadequacy of the 
schools so far as these pupils are concerned may be sup- 
posed to lie in their failure to promote pupils quickly up 
to the school position of their equals. On account of 
the expense of special teachers such pupils presumably 
could not be given a chance to make up the school sub- 
jects which they had missed and could not be advanced to 
the grades requring this knowledge. Whenever this is 
the case or under any circumstances which keep the pupil 
behind the school class of his intellectual equals, we have 
a fundamental cause of distaste for school work. No 
wonder that such pupils dislike school, become disgruntled 
and stubborn, run away and rebel at the treatment they 
receive under the traditional school system. One can 
hardly blame a self-respecting boy, forced to remain be- 
hind his peers, for breaking away from the lock step, 
playing truant and seeking his education in the streets. 

The trouble is not with the school authorities alone. 
They are doing about as well as can be expected with 
the funds which the people have been willing to provide. 
The public must be educated up to the recognition of the 



206 DEFICIENCY AND DELINQUENCY 

fact that every child in the school should be allowed to 
progress as rapidly as his abilities permit. The public 
schools of Mannheim, Germany, are the great illustra- 
tion of what can be done to bring the school instruction 
close to the varying degrees of capacity among the pupils. 
In the Mannheim schools children may carry from four 
to eight years of the regular curriculum in eight years, 
and the brighter pupils may also take additional subjects. 
The Industrial School in Cleveland has demonstrated 
that some 14-year-old boys two years backward in school 
may, with special help, be successfully prepared for high 
school with about as much likelihood that they will con- 
tinue the high school course as the ordinary boys (107). 
It is self-evident that a boy with ability to carry a 
higher grade of work cannot ordinarily be allowed to 
skip one or two classes without special instruction and 
be expected to succeed with studies which require pre- 
liminaries that he has had no opportunity to learn. The 
necessary knowledge and sufficient skill in particular hab- 
its of thought needed could probably be acquired in a 
brief time under the right sort of special instruction. It 
is not sufficient that special classes for pupils mentally 
backward should be provided in the schools. They will 
not take care of this problem, which has to do mainly 
with pupils intellectually capable of carrying the work 
of a higher grade than that in which they are placed. 
These children can now be found by means of mental 
tests and they should be assisted in making up the inter- 
mediate work by collecting them into redemption groups, 
so to speak, where they can have individual instruction. 
In the public schools of Faribault, Minnesota, the plan 
of thus picking out older minds in a class and promoting 
them one or two grades with very little extra instruction 
has been successfully tried in an experimental way. 



BAD SCHOOL ADJUSTMENT AND DELINQUENCY 207 

If all of the children in a school system who are thus 
seriously out of intellectual adjustment cannot be cared 
for, it is plain that the children in danger of delinquency 
might well receive the first attention, since the lack of 
adjustment with these may cause the most serious social 
consequences. That the problem is more acute among 
the serious offenders in juvenile court than among school 
children generally is indicated by a comparison with God- 
dard's figures for school children generally in a typical 
community tested with the same scale. If we select from 
his tables only that group of mental ages which could 
actually be in a class ahead or behind their mental de- 
velopment, we find that only 20% of this group would be 
outside the standard of 6 and 7 years in the first grade, 
etc., as compared with 52% of our detention home group 
on the same basis. On the other hand Terman's records 
with the Stanford scale (193) indicate 44% of ordinary 
children similarly maladjusted to school. This con- 
dition should probably be regarded, therefore, as a sup- 
plementary stimulus for delinquency rather than a funda- 
mental cause comparable with mental retardation. 

While this lack of adjustment is undoubtedly the most 
pressing training problem connected with juvenile de- 
linquency, we must not expect that when it is solved we 
shall have eliminated the problem of mental backward- 
ness of delinquents as a class. The most that we could 
expect from perfect adjustment of the school work to 
mental ability would be that the average amount of school 
retardation for the group would be materially reduced. 
How much retardation in school relative to the life-ages 
would still remain, cannot be determined on account of 
the uncertainty of the tests for older ages and the factor 
of volition. For the mentally deficient pupils still re- 
maining behind the regular pupils it is necessary to pro- 



208 DEFICIENCY AND DELINQUENCY 

vide other special classes. In these classes or schools the 
feeble-minded children would remain for their entire 
school course. 

That the correction of the lack of adjustment is a 
much more agreeable and hopeful task than the care for 
deficients is shown by the facts regarding the detention 
home group in Table IX. There is at least the possibility 
that 10 of the school laggards in this group of serious 
delinquents might be brought up to a satisfactory grade. 
Discount this prospect as you may, it is still to be com- 
pared with the fact that no actually feeble-minded boy 
can ever, by special instruction, be brought up to a satis- 
factory school grade. Moreover, we might expect that 
30 of the 84 laggards might, by special help, catch up 
one or more grades. 

That the correction of lack of school adjustment is a 
bigger problem in connection with juvenile delinquency 
than the detection and isolation of the mentally unfit can 
only be said in relation to the numbers affected. Tak- 
ing the lowest estimate of those in the detention home 
group out of adjustment with their school environment 
it was at least 30, while only 9 of that group fell below the 
borderline of passable intellects and only 2 were surely 
feeble-minded. If one guessed as we have on the basis 
of school position that a maximum 6% of the ordinary 
juvenile delinquents in Minneapolis might be feeble- 
minded, who would venture to guess that ill-adjustment 
of school to mental ability affects so small a proportion? 
On the other hand one feeble-minded person, through 
the transmission of his deficiency, may, perhaps, do more 
damage to society than many intelligent delinquents. 
Who shall say? Certainly both the isolation of the feeble- 
minded and the adjustment of school training are vitally 
important problems in the care of juvenile delinquents 



BAD SCHOOL ADJUSTMENT AND DELINQUENCY 209 

today. Nobody can say that one is more important than 
the other except from a special point of view. From 
the eugenics standpoint feeble-mindedness is more im- 
portant; from the point of view of the numbers affected 
and the skill required for training the child, there can be 
little question but that the correction of bad adjustment 
to school environment is the bigger problem. When 
one considers how much of the child's time is spent out 
of school, at home, with playfellows, or at work we cannot 
be sure that other external influences might not ulti- 
mately be found to be more important in connection 
with juvenile delinquency than either the school life or 
mental incapacity. The further consideration of the 
causes of delinquency we shall now make the subject 
of a broader inquiry. 



CHAPTER XL DEFICIENCY AS A CAUSE 
OF DELINQUENCY 

In a preceding chapter we have shown the frequency of 
tested deficiency among various types of delinquents. 
We may now further consider the significance of this as- 
sociation of delinquency with deficiency. The best plan 
for discovering its meaning is provided by the technical 
method of correlation. The data in the published re- 
ports of the score or more of investigations which I have 
reported is wholly inadequate for following out this 
method. We must, therefore, for the present content 
ourselves with noting what has been discovered by the 
better analysis of similar data which was supplement- 
ed by the necessary information as to the distribution of 
the different types of crime in the corresponding general 
populations. To this we can add certain correlations in 
connection with the small Minneapolis group of tested 
juvenile delinquents. 

We are indeed fortunate to have the fundamental work 
of Dr. Charles Goring on 'The English Convict/ ' from 
which to formulate a point of view regarding the relation 
of deficiency and delinquency. This work represents 
ten years labor in making observations, collecting, tabu- 
lating, and statistically evaluating data on 3000 convicted 
men, who were found in the English convict prisons where 
they had been sent after conviction in the higher courts 
because! guilty of grave or repeated offenses. It was 
carried out with the co-operation of a corps of workers 
who had the help of Professor Karl Pearson and his assist- 
ants at the Biometric Laboratory of the University of 
London, in the statistical reduction of the almost over- 
whelming mass of data. By the large use of partial 

(210) 



DEFICIENCY AS A CAUSE OF DELINQUENCY 211 

correlation the relative influence of various factors upon 
criminality was investigated as it never had been before. 
It is, of course, not possible to reproduce here the con- 
clusions of this monumental work which should be made 
more widely available in the libraries of this country. We 
shall, however, select certain conclusions which bear most 
directly upon our problem and which rest upon well es- 
tablished statistical deductions, and compare them with a 
few other studies which have contributed interesting 
side lights upon the causes of delinquency. 

A. The Chances of the Mentally Deficient Be- 
coming Delinquent. 

4 'Every feeble-minded person is a potential criminal," 
says Goddard in his work on Feeble-Mindedness (112, 514), 
and this sentiment finds an echo in the emotions of many 
social workers. On the other hand we have the careful 
work of Bronner in which she compares by their test re- 
cords a group of delinquent women with groups selected 
from night classes and the servant class who had never 
been known to be immoral. On the average she finds 
that the delinquents do not test below her servant group. 
She says: 

'Thus, though our delinquents are not as capable as 
their sisters, many of them from congested districts, who 
in other ways are proving themselves ambitious [the 
group from night classes,] yet they are no less equipped 
intellectually than others who are earning a livelihood 
and caring for themselves without coming in conflict with 
the law in the least. Whatever their mental status might 
be, measured by other means, the fact remains that there 
is no necessary correlation between their immoral or 
criminal tendencies and their intellectual ability and 
that others, no more endowed than they, are fighting 



212 DEFICIENCY AND DELINQUENCY 

life's battles without manifesting the same immoral or 
criminal tendencies' ' (112, p. 43). 

What portion of these moral household servants of 
equal ability with the delinquents may later fall under 
temptation, we, of course, cannot say. Neither can we 
say that any of the delinquents would test deficient, since 
we do not know the border lines of deficiency with the 
tests which were used. The conclusion, however, is 
clear that, if corresponding grades of intellect may be 
delinquent or not at maturity, we must be cautious in 
assuming that the lowest grades of intellects would all 
become delinquent if not under supervision. 

What chances we are running by allowing feeble-minded 
individuals to be abroad might be determined if we could 
find out the probability of tested deficients becoming 
delinquent. This question cannot be answered by show- 
ing for a single year or a period of years that crimes are 
relatively more common among the defective classes, 
although such figures give some impression of the danger 
of deficiency to the community. 

Kinberg, for example, calculates that in Sweden during 
the years 1901-1907 murder was relatively 200 times as 
common as among those not in institutions, but lacking 
criminal responsibility through insanity or deficiency, as 
among those who were responsible, arson was 72.5 as 
common, manslaughter 12.63 times, other injuries to 
property than arson 6.55, rape 6.1 times, infanticide 
4.59 times, larcency 0.99 times, and fraud 0.26 times 
(132). The data were based upon the reports of the 
Royal College of Health which makes the diagnosis as to 
criminal responsibility that is required for all cases in 
which this question arises. Such examinations, it is 
estimated, miss at least 15% of the deficient criminals. 



DEFICIENCY AS A CAUSE OF DELINQUENCY 213 

Goring gives a table which shows what crimes are most 
likely to be committed by deficients. He found that 
10% of the convicts in England and Wales were definitely 
treated in prison as deficient, and he estimated that 0.5% 
of the non-criminal population were equally deficient. 
His table is based upon the tabulation of 8,290 crimes 
past and present of 948 English convicts (Fig. XXXIX, 
p. 258). It is given below: 

TABLE XVII 

Goring's Data as to the Percentage of Mental Defectives 
Among Men Convicted of Various Offenses. (948 Convicts) 

Firing of stack 52.9% 

Wilful damage, including maiming of animals 22 . 2 

Arson 16.7 

Rape (child) 15.8 

Robbery with violence 15 . 6 

Unnatural (sexual) offenses 14 . 3 

Blackmail 14.3 

Fraud 12.8 

Stealing (and poaching) 11.2 

Burglary 10.0 

Murder and murderous intent 9.5 

Rape (adult) 6.7 

Receiving 5.1 

Manslaughter 5.0 

Coining 3.3 

Wounding, intent to wound, striking superior officer 2.9 

Embezzlement, forgery, fraudulence as trustee, bigamy, 

performing illegal surgical operation 0.0 

General population 0.5 

Another table from Goring shows which groups of 
crime are most likely to be committed by the deficients 
compared with the frequency of that type of crime in the 
general population. It is reproduced in part below. 



216 DEFICIENCY AND DELINQUENCY 

ficients will be convicted of crime at some time in their 
lives. If instead of taking this estimate of 10% of the 
criminals being deficient we had taken 20%, then the 
probability of a deficient individual being convicted of 
crime would rise to .77. 

On the basis of our summary of tested delinquents in 
the last chapter it seems extremely conservative to sup- 
pose that 10% of the manifest and potential criminals are 
as deficient mentally as the lowest 1.5% of the general 
population. Even with this assumption we find that the 
chances would be 48 out of a hundred that a person of 
this degree of deficiency would be convicted of crime. 

These estimates, I believe, afford a telling argument 
for the indefinite isolation of at least those who are in the 
lowest 0.5% mentally on the ground of their potential 
criminality, independently of any question of the danger 
to society from the hereditary transmission of the diathesis 
of deficient delinquency. 

We have heard much in recent years of the particular 
danger of allowing the better grade of feeble-minded, 
especially the morons, to be abroad in the community. 
Time and again it is asserted that it is this class of defic- 
ients which is most likely to become delinquent. There 
is a widespread confusion here between the statement 
that criminals in absolute numbers are drawn more fre- 
quently from the moron class and the statement that 
morons are relatively more likely than imbeciles or 
idiots to become delinquent. To the first alternative 
there would be no objection since morons are much more 
frequent than the lower grades of deficiency. On the 
other hand if morons are relatively more likely to be 
delinquent than imbeciles, then we should expect those 
just above the morons in ability to be more likely than 
morons to be delinquent. The technical answer to the 



DEFICIENCY AS A CAUSE OF DELINQUENCY 217 

problem whether the lower grades of deficiency are more 
likely to become delinquent could be best reached by 
discovering the correlation of delinquency with the differ- 
ent grades of deficiency. 

Goring's data throw some light on this question since 
he has found the correlation between grades of intelli- 
gence and the degree of recidivism and also between in- 
telligence and the frequency of bad reports in the penal 
institutions where the convicts were held. In both cases 
the tendency is clear for the weak-minded and imbecile to 
be more frequently convicted and to be reported more 
frequently for bad conduct than for the higher grades of 
intelligence which he classifies' as unintelligent, fairly 
intelligent and intelligent. The correlation coefficient 
with frequency of convictions relative to time out of 
prison is -.16 and with frequency of bad reports is -.33. 
The correlation ratios are slightly higher in both cases. 
On the other hand the more intelligent are likely to be 
given longer sentences, the correlation being +.10.* It 
might be contended that his distinction between the low- 
est grades of intelligence is not objective and not very 
clear; but that the general tendency of the regression 
lines would be reversed at the lower extreme seems very 
improbable. In other words there is some reason to 
suppose that, relative to their numbers, the idiots and 
imbeciles would be more likely to be delinquent than the 
more intelligent feeble-minded provided none was con- 
fined in an institution. No idiot and few, if any, imbeciles 
could survive honestly in any environment without assist- 
ance. 

How closely the degrees of immorality are associated 
with the degrees of deficiency remains one of the most 

*See the next section for the significance of these coefficients of 
correlation. 



218 DEFICIENCY AND DELINQUENCY 

important problems to be answered authoritatively by 
the correlation of these traits when properly measured. 
That the greater degrees of immorality and of deficiency 
are on the whole associated and not opposed we have 
good reason to believe, but there are undoubtedly ex- 
amples in which the degree of immorality or delinquency 
is out of proportion to the degree of deficiency. The fact 
that certain instances are found of moral imbeciles with- 
out corresponding intellectual deficiency, which has been 
noted by Stern (188, p. 75) and by Anton (67), does not 
of course determine the direction of the tendencies. We 
must base our deductions as to the danger of delinquency 
among lower and higher grades of deficients on oui knowl- 
edge of the general tendencies. Are morons, relative 
to their numbers, more dangerous to the community 
than lower grade deficients? We must not make the 
absurd deduction that because morons are most numerous 
they are most likely to be delinquent and should therefore 
be most carefully isolated or supervised. 

B. The Correlation of Deficiency and Delin- 
quency. 

Modern statistical methods afford the ultimate quanti- 
tative tool for determining the cause of delinquency, 
whether or not we also require that the data should be 
assembled under experimentally controlled conditions. 
The rapid strides which have been made in answering 
this fundamental question of criminology may be judged 
by noting the treatment of it in such a work as Goring's 
compared with the impressionistic literary style which 
has prevailed. Illustrations of particular cases, opinions 
subconsciously formulated by experts from wide exper- 
ience in dealing with delinquents, even the votes of the 
majority of leaders in the field, give way before the acid 



DEFICIENCY AS A CAUSE OF DELINQUENCY 219 

test of measurement of tendencies in human traits just 
as poorer methods succumbed in the Middle Ages in the 
realm of the physical sciences. Quantitative determin- 
ations can no longer be brushed aside with a smile on the 
supposition that statisticians are the biggest liars. They 
must be answered by better data or more refined methods. 
The form of the discussion of social questions has changed. 
Correlation is a powerful new weapon for attacking these 
problems which promises to go far beyond the range of 
earlier blundering methods. 

While partial correlation affords an ideal approach to 
answering the question of causation, it has been used 
only to a very limited extent. The necessary data for 
comparing the closeness of relationship of various sug- 
gested causes of delinquency are not available and too 
few who are interested in social problems have appreciated 
the significance of the method. We should, therefore, 
lay especial emphasis on the measurement of the correla- 
tion of deficiency and criminality by Goring. He labor- 
iously assembled the only data which are sufficiently 
extensive to allow much reliance to be placed upon their 
statistical reduction. In his use of correlation, moreover, 
he acted under advice from the main center for this work 
at the Galton Laboratory in London. 

If those who were "mentally defective ,, under Goring's 
designation were always convicted of crime and none 
of those who were not defective were ever convicted of 
crime, the measure of the relationship between criminality 
and deficiency would be expressed by a correlation co- 
efficient of +1.00. If there were no relationship what- 
ever between deficiency and criminality the coefficient 
would be 0.00. If the deficients were never convicted of 
crime and the non-deficients were always criminal the 
coefficient would be -1.00. Intermediate degrees in the 



220 DEFICIENCY AND DELINQUENCY 

relationship of these tendencies would then be represented 
by decimals which would be either positive or negative, 
depending upon whether the traits were associated to- 
gether or were opposed. The coefficient which he found 
for the male population was +.6553, which was much 
higher than that for any other constitutional or environ- 
mental factor which he measured. 

In calculating this correlation Goring regarded 10% 
of the criminal male population as defective. He found 
that this was in agreement with the common tendency 
in English convict prisons to class officially about this 
portion of the criminals as defectives and needing care. 
He also assumed that 0.46% of the non-criminal male 
population in England and Wales was defective, the pro- 
portion suggested by the report of the Royal Commission 
on Feeble-mindedness. By a careful computation he 
calculated that 7.2% of the males either have been or 
will be convicted of crime before they die. He then 
constructed the four-fold table on the basis of these esti- 
mates as applied to the 948 convicts whom he examined 
as to their mental condition. The coefficient was then 
calculated by Pearson's method for a four-fold table. 
This method assumes that the mental ability and the 
tendency to criminality are distributed normally in the 
population and that the difference in numbers between 
the criminal and the non-criminal, deficient and non-de- 
ficient are not too great. In case the percentage of de- 
fectives among the criminals were taken as 20% instead 
of 10% the correlation would be increased to .79. 

Using the same four-fold method we may calculate the 
correlation between deficiency and juvenile delinquency 
among Minneapolis boys. It is necessary to make a 
good estimate of the proportion of boys who annually 
become delinquent in Minneapolis for the first time, and 



DEFICIENCY AS A CAUSE OF DELINQUENCY 221 

of the proportion of these boys who are correspondingly 
deficient. Fortunately these comparisons can be made 
fairly accurately on the basis of the reports for the year 
1915 and of our tests of juvenile delinquents. We may 
use a minimum and a maximum estimate of deficiency 
among the delinquents corresponding to those that tested 
below borderlines which represented the lowest 0.5% and 
the lowest 1.5% of the population of corresponding ages. 
We need to assume that the frequency of tested deficiency 
among the boys found delinquent would correspond within 
these limits to the frequency among the Glen Lake group. 
The indices for the amount of school retardation in these 
two groups (Table XIV) indicate that this is a liberal 
estimate. We must also assume that the proportion of 
juvenile delinquents for the year 1915 may be regarded as 
typical for a series of years. The number of new cases of 
boys in juvenile court in 1915 was within 18 of the median 
number for the last four years. The result of these esti- 
mates is Table XIX for the minimum estimate of defic- 
iency. A similar table for the maximum estimate of de- 
ficiency would be the same, except that the proportion of 
all boys of these ages who were deficient would be 1.5%, 
and of the delinquent group, 7.3%. 

The computation of the correlations by Pearson's tetra- 
choric r shows the relationship between juvenile delin- 
quency and deficiency among boys to be .16, P. E. .07, on 
the minimum estimate of deficiency. On the maximum 
estimate the correlation is .29, P. E. .05. In order to 
make a closer comparison between Goring's calculation 
and my own I have recalculated the correlation for 
his group on the assumption that 0.5% of the general 
male population were deficient and that 1.29% would 
be convicted felons of the type among which he found 
10% to be deficient. This brings the minimum correla- 
tion for his figures to .59, P. E. .03. 



222 



DEFICIENCY AND DELINQUENCY 



TABLE XIX 

Four-Fold Correlation Table for Juvenile Delinquency and 
Deficiency in Minneapolis (Minimum Estimate). 

Boys 8-16 Years of Age 





Non-Deficient 


Deficient 


Total 


Non-Delinquent 


22,305 


109 


22,414 


Delinquent 


268 


4 


272 


Total 


22,573 


113 


22,686 



The tota number of boys is taken from the census of school children 
for 1915-16 compiled by the attendance department of the Board of 
Education. It includes those in public, parochial and private schools 
and those not attending. The number of delinquent boys is taken from 
the report of the Juvenile Court of Hennepin County, Tables H and I. 
The number of repeaters and the proportion of delinquent cases dis- 
missed at the hearing are subtracted from the total number of new 
cases. 

The difference between a correlation of .29, the highest 
I found, and .59, Goring's lowest result, indicates that con- 
viction for felony in Great Britain is more closely associated 
with deficiency than juvenile delinquency is associated 
with deficiency in such communities as Minneapolis. It 
is to be remembered, however, that Goring's calculation 
gave the convicts a life-time in which to be convicted, 
while ours gave the boys only 16 years. The relation of 
potential delinquency after 16 years of age to deficiency 
might be greater among Minneapolis males than the cor- 
responding relation we found among the boys; but the 
difference in these correlations is more easily explained 
by supposing that the type of serious delinquency re- 
presented by sentences to penal servitude, in England at 
least, is more closely related to deficiency than are the 
lighter forms of delinquency found among the youth of an 
American city. 



DEFICIENCY AS A CAUSE OF DELINQUExNCY 223 

The most significant fact demonstrated by the correla- 
tions between juvenile delinquency and deficiency is that 
there is a positive relationship which is significant in 
amount. With the maximum estimate the correlation 
is nearly 6 times its error. This is the first time that the 
relationship has actually been calculated in connection 
with any group of juveniles. We can say that when a 
Minneapolis boy is below the average in tested ability 
for his age, he is most likely to be .16 to .29 of the same 
amount below the average in legal conduct, both measure- 
ments being in corresponding units. 

What then, is the significance of correlation in answer- 
ing the problem of causation? So far as the statistical 
method itself is concerned it shows only a mathematical 
functional relation between the conditions measured, not 
a physiological relationship. In other words a correla- 
tion between deficiency and delinquency might be ex- 
plained by both conditions being related to some more 
fundamental factor which might be the causal factor in- 
volved. One cannot reason from correlation to direct 
causal connection. On the other hand, by correlation 
we may directly compare the relation between any one 
trait and various factors. We can find out, for example, 
whether the association of delinquency with deficiency 
is closer than the association of delinquency with other 
factors which it has been suggested are causes of delin- 
quency. Goring's work allows us to compare the correla- 
tion of the tendency to be convicted of crime with de- 
ficiency and with many other constitutional and environ- 
mental factors which have been measured, and thus our 
attention may at once be directed to that factor which 
the present evidence indicates as most fundamental. 
Unless the measurement of the various factors is shown 
to be seriously faulty or incomplete the outcome should 



224 DEFICIENCY AND DELINQUENCY 

determine our point of view as to the main cause of de- 
linquency, until new evidence is forthcoming. This is 
the problem of the next section. 

C. The Causes of Delinquency. 

As we have noted above,- the correlation of delinquency 
with various factors should give us a scientific point of 
view as to the main causal influence in criminality. 
Thanks to Dr. Goring this work has recently been carried 
far. His findings mark a new and higher scientific level 
in the study of criminology. Xo data are now available 
which modify his position in any important regard. I 
shall therefore, attempt to give his evidence in the brief- 
est possible manner, hoping that it may lead to a closer 
reading of his basal investigation. 

a Constitutional factors. 

First comparing a dozen factors in the individual's own 
constitution which may be measured by the death rates, 
Goring found the tendency to be convicted of crime was 
correlated most closely with alcoholism, .39; sexual profli- 
gacy (syphilis and aneurism^. .31; and epilepsy, .26; while 
it was found to correlate with intelligence, .66. The 
closeness of the relationship of defective physique to 
criminality was expressed by coefficients of .18 and .19. 
Among the inner factors investigated were many of 
Lombroso's characteristics of the so-called criminal phys- 
iognomy of which so much use is made by phrenologists, 
such as asymmetries, projection of the chin, complexion, 
form of the face and features, kind of hair, tattooing, 
left-handedness, temperament, etc. 

Following this analysis, we find that alcoholism, epil- 
epsy, and probably social profligacy are closely associated 
with intelligence as well. By means of partial correla- 



DEFICIENCY AS A CAUSE OF DELINQUENCY 225 

tions he shows that when individuals of the same degrees 
of intelligence are compared there is only slight additional 
relation between alcoholism or epilepsy and criminality. 
The relations to these other conditions are therefore ac- 
cidental, depending upon the fact that deficients are more 
likely to be alcoholic and epileptic, the fundamental con- 
stitutional factor being intelligence. Among over forty 
physical and mental factors, the only other condition 
which he found to have significant relation to criminality 
is a generally defective physique as shown by height and 
weight, neither of which is correlated with intelligence. 

Regarding the above inner factors he summarizes his 
conclusion as follows: 

"Our final conclusion is that English criminals are 
selected by a physical condition, and a mental consti- 
tution which are independent of each other — that the 
one significant physical association with criminality is 
a generally defective physique; and that the one vital 
mental constitutional factor in the etiology of crime is 
defective intelligence" (20, p. 263.). 

(b) External factors. 

Turning now to certain factors which might be supposed 
to be important mainly as environmental influences, 
Goring studied the length of imprisonment and the fre- 
quency of reconvictions for crime relative to the periods 
of freedom as two measures of the degree of recidivism 
among his criminal group. He measured the correlation 
between the degree of recidivism and such outer factors 
as formal education classified by the kind of school train- 
ing, whether received in the elementary school, secondary 
school, or at a compulsory industrial or reformatory 
school for delinquents, also formal education as measured 
by the age at leaving school; effective education as 



226 DEFICIENCY AND DELINQUENCY 

measured by the grade in school reached at the time of 
leaving and by the educational grade assigned the con- 
vict in the prison school; regularity of employment clas- 
sified under the headings regular, occasional, voluntarily 
unemployed, unemployable; alcoholism under estimates 
as to the convicts' intemperance, temperance or abstinence; 
family life, in which the standard of life was classified as 
well-to-do. prosperous poor, poor, very poor, and desti- 
tute; the influence of maternal authority measured by 
the age at death of the mother, order of the subject in 
the family, and number in the family, thus reaching the 
question of only sons and of size of family; nationality; 
and finally the relation of age at which the first sentence 
was received and the nature of the sentence to subse- 
quent convictions. 

The significance of the relation of these external in- 
fluences upon the degree of recidivism is not directly com- 
parable with the influence of these factors upon the tend- 
ency to be convicted or not to be convicted of crime at 
all, as he carefully explains. Since the distribution of 
the above factors in the population at large is not known, 
the relationship to criminality in general could not be 
measured for the outer factors as it was for the inner 
factors discussed previously. Reserving, then, our judg- 
ment as to how closely these environmental factors may 
be related to the criminal tendency not represented by 
recidivism, we can reach important conclusions as to 
their relation to the degree of recidivism. Only one of 
the coefficients was found to be large enough to be twice 
its probable error, so that as a whole they were not at all 
significant. He summarizes his conclusions as follows: 

"The relative values of these contrasted coefficients 
demonstrate effectively and conclusively one truth: that 
an adverse environment is related much more intimately 



DEFICIENCY AS A CAUSE OF DELINQUENCY 227 

to the intelligence of the convicts than it is to the degree 
of their recidivism, or to the nature of the crimes they 
commit. Moreover, since mental defectiveness is closely 
related to crime, an easily imagined corollary to this 
truth is that the mental defectiveness of the convict is 
antecedent to his environmental misfortunes, rather than 
that his unfortunate circumstances have been responsible 
for the mental defectiveness of the convict, and his lapse 

into crime " 

"From the general trend of the results tabulated above, 
our interim conclusion is that, relatively to its origin in 
the constitution of the malefactor, and especially in his 
mentally defective constitution, crime in this country is 
only to a trifling extent (if to any) the product of social 
inequality, or of adverse environment, or of other mani- 
festations of what may be comprehensively termed 'the 
force of circumstances' " (20, p. 287-288). 

The caution which we have noted above, as to the in- 
fluence of outer factors having been measured in relation 
to recidivism rather than to criminality, becomes more 
important when we find that the correlation of high in- 
telligence with frequency of convictions is also low, only 
-.16 and to fractions of a year imprisoned +.10. Since 
the relation of intelligence to criminality in the general 
population is +.66, we cannot be at all sure that these 
outer factors, or some of them, might not also be much 
more closely related to criminality than they are to re- 
cidivism. Besides this caution we might also urge that 
some of the most important outer influences have not 
yet been evaluated by correlations. We know nothing, 
as yet, except by inference about the correlation of de- 
linquency with the influence of bad companions outside 
the home, bad school adjustment, the effect of broken 
families aside from the early death of the mother, absence 
of proper recreation, and many other stimuli for delin- 
quency which social workers have been studying for years 
by less conclusive methods. 



228 DEFICIENCY AND DELINQUENCY 

Just to recall the frequency of some of these other con- 
ditions associated with the environment of the youth we 
may note that Aschaffenburg says that Abanel found in 
Paris "among 600 criminals under twenty years of age in 
303 cases the family life of the parents was destroyed ow- 
ing to death, divorce, desertion, illicit relations, or to 
some similar cause' ' (208, p. 133). Again he states that 
in 1841 Father Mathew, by making 1,800,000 total ab- 
stainers temporarily reduced serious crimes in Ireland 
from 12,096 to 773 per annum in a period of three years. 
Miss Rhoades by a personal evaluation of many factors 
involved in each of 81 random cases of juvenile delin- 
quency in Chicago found that the main cause in 67 cases 
was some home condition and in 9 others it was a special 
temptation in street gangs, while only in 5 was the main 
cause mental subnormality (171). That nearly half of 
the juvenile delinquents come from broken families, 
affected by death, divorce, or desertion has been frequently 
shown. A study of more than a thousand successive 
cases in the Minneapolis juvenile court by Miss Finkle 
showed that 39% of them were from families not normally 
constituted, families in which one of the natural parental 
guardians of the children had been removed (105). We 
also have an important study of the relation of the de- 
linquent child to his home by Breckenridge and Abbot 
(82). 

While there is always a possibility of finding some other 
factor closely related to delinquency and independent of 
capacity, nevertheless we should hardly urge this pos- 
sibility at the present time as overweighing the accumu- 
lation of negative evidence which has been assembled in 
recent years, especially at the Galton Laboratory. We 
should remember that many so-called outer influences 
are, like the temptation to drink, related to the incapacity 



DEFICIENCY AS A CAUSE OF DELINQUENCY 229 

which precedes the temptations. There is also good rea- 
son to suppose that many bad environmental surround- 
ings result from rather than cause deficiency. Even 
broken homes may be a result of incapacity, to which 
undoubtedly early death is related. The first essential 
for social philosophers is to recognize that so-called en- 
vironmental factors may have their corresponding inborn 
correlates. This is almost invariable with home con- 
ditions. The problem is to weigh the relative importance 
of these outer and inner factors on the same individuals. 

(c) Weighing heredity against environment. 

Both subjective and objective methods have been used 
in trying to determine whether heredity or environment 
has the most influence upon criminality. The earlier and 
subjective method is one for which Gruhle is perhaps the 
leading advocate. By this method an expert with wide 
experience judges the relative effect of inner and outer 
causes of delinquency in particular cases. In his study 
of 105 minor delinquents in a German industrial school 
Gruhle, after a thorough and systematic clinical and soc- 
iological study of each person, gave his judgment whether 
heredity or environment was the main cause of delin- 
quency in the case. In his summary he concluded that 
in 9 cases the fundamental cause was found in the envir- 
onment, in 8 cases in environment plus a subordinate 
influence of heredity, in 41 environment and heredity 
were balanced, in 20 cases heredity was the main influence 
but environment was a subordinate factor and in 21 
heredity was considered the causal factor. This shows 
that, when each case was estimated separately, in his opin- 
ion heredity on the whole turned out to be more important 
than environment for this group. By the same subjec- 
tive method Gruhle weighs the influence of family taints 



230 DEFICIENCY AND DELINQUENCY 

such as mental abnormalities, deficiency, and drunken- 
ness as against the hereditary influence in crime, and comes 
to the surprising result that in 9 cases where both parents 
were abnormal mentally or drunken in only two cases 
was heredity the predominant cause of the delinquency, 
while in 7 cases where neither parent showed these taints 
the delinquency was invariably explained by heredity. 
The group whose delinquencies were in his opinion main- 
ly due to heredity showed, curiously enough, less family 
taints from nearly every point of view. He concludes: 

"The knowledge that so many of the criminal youths 
are abnormal is indeed very significant for the therapeutic 
treatment of the social offenders, for the choice of the ways 
which should be used to improve the youths; but this 
knowledge has no significance for establishing the causes 
of delinquency The abnormal par- 
ents really have more children who are abnormal and 
under the average in capacity, but their children are 
actually more seldom delinquent because of the natural 
tendencies than the children of normal parents' ' (121). 

Healy has followed a similar plan in subjectively weigh- 
ing the influence of various factors as causes of the de- 
linquency of 823 recidivists before the Psychopathic 
Institute at the Chicago Juvenile Court. Although he 
does not directly estimate hereditary and environmental 
factors as such, his summary of these estimates of separate 
cases shows the main cause of delinquency in 455 of these 
cases to be some form of mental abnormality or peculiar- 
ity. Abnormal physical conditions, including excessive 
sex development accounted for 40 more. His other 
causes, which embraced only 26% of the cases, might 
possibly be regarded as directly environmental. They 
included defective home conditions, including alcoholism, 
bad companions, mental conflicts, improper sex exper- 
ience and habits, etc. 



DEFICIENCY AS A CAUSE OF DELINQUENCY 231 

Thus we find that the two most important expert esti- 
mates of individual cases after exhaustive study apparent- 
y agree in placing the main causal influence on factors 
which are predominately inner rather than outer. The 
most serious objection to this method of approaching 
the problem is that we have no way of determining how 
far such a result is the effect of the expert's unintentional 
bias. Gruhle's analysis of his delinquent group, however, 
raises very clearly the question whether the total influence 
of heredity may not be markedly greater in the production 
of delinquency than merely the heredity influence through 
mental deficiency and abnormalities in the families. 

A better method of evaluating the relative influence 
of heredity and environment would avoid the danger of 
subjective bias by studying objectively measured factors. 
With either the subjective or objective method correla- 
tion affords a better way of statistically handling the re- 
sults. The best approach to an objective study of the 
inner and outer causes of delinquency by the correlation 
methods is furnished by Goring. The ingenuity of the 
biometrical procedure in applying correlation to resolving 
this perennial question of heredity and environment must 
be recognized by all who take the time to understand 
its methods. We can only briefly consider the results 
of Goring's chapter on 'The Relative Influence of 'Inher- 
itance' and 'Contagion' upon the Ocurrence of Crime and 
the Production of Criminals.' ' 

This work conclusively demonstrates that crime runs 
in families. The probable value of the correlation be- 
tween conviction for crime on the part of the father and 
son was found to be .60, while the correlation between 
mother and son was only slightly less. The tendency 
to resemble brothers in criminality was shown by the 



232 DEFICIENCY AND DELINQUENCY 

probable fraternal correlations of .45. Whether this 
family resemblance is mainly through nature or nurture 
is the problem. 

In analyzing the influence of the home he uses partial 
correlation and finds that the correlation between age 
at first conviction and the number of convictions for a 
constant period of time after the first conviction is -.243. 
"From the value and sign of this coefficient, we see that 
the earlier in life a child commits a criminal offence, and 
is consequently removed from his home, the worse crim- 
inal does he become; and, accordingly, we conclude that 
criminal proclivities are more bred in the home than 
inoculated there" (119, p. 368). This argues against 
the predominant influence of the home training or example 
as explaining family resemblance in criminality. Never- 
theless, it would seem that the result might also be in- 
terpreted as meaning that the contact with other de- 
linquents and official discipline outside the home at a 
more impressionable age notably increases the tendency 
to recidivism. 

Besides the argument as to the earlier removal from 
home, we have a test of the question whether those kinds 
of crime that are most influenced by contagion show 
closer correlation within the family. His statement of 
the results is as follows: 

"Our table 177, above, starting with crimes of fraud, 
passes to stealing and burglary — professional crimes, 
where the influence of criminal contagion should be the 
most intense; and then progressively to violence, arson 
and sexual offenses, in which last it is difficult to under- 
stand how the influence of example could have any effect 
at all. We can understand the influence of parental 
training in the original moulding of a professional burglar 
or thief, and, to a certain extent, it is conceivable that the 
constant spectacle of the lack of control in parents might 



DEFICIENCY AS A CAUSE OF DELINQUENCY 233 

lead their offspring to emulate them in acts of unlawful 
violence. But, that parental example could play any 
part of importance in the perpetration by their offspring 
of crimes such as arson and wilful damage to property, and, 
particularly, of sexual offenses, is not reasonably to be 
supposed. As seen in the above table, 177, the parental 
correlation for sexual crimes, and crimes for wilful damage 
to property is from .45 to .5; for stealing, it is from .48 
to .58. We would assume then, from this evidence, that 
the tendency of the inherited factor in criminality is from 
.45 to .5, and the intensity of criminal contagion is any- 
thing between .05 and .1" {20, p. 367). 

Other evidence as to the relative influence of heredity 
and training, which Goring suggests, is in connection with 
the difference in influence of the two parents. If the 
contagion were from either the mother or father alone, 
the difference in resemblance to that parent and the other 
might indicate the strength of the contagion. The dif- 
ference amounts to about .05. This again, in his opinion, 
gives some idea of the relative importance of nature and 
nurture within the family. The measure would not be 
complete unless the hereditary tendency to resemble 
mother and father were equal and the contagion were 
all from one parent. 

Husbands and wives tend strongly to resemble each 
other in crime, the correlation being .6378. This re- 
semblance is of course not due to heredity. Goring be- 
lieves that it is not due to contagion and argues that be- 
sides the subjective tendency for the criminals to associate 
together, there is here a large element of conscious choice 
of a mate among the criminal classes, especially as the 
criminal woman shows the tendency most clearly and 
would not be able easily to get a non-criminal husband. 

This work of Goring illustrates how an important be- 
ginning has been made in applying the correlation method 
to objective records, in order to weigh the relative im- 



234 DEFICIENCY AND DELINQUENCY 

portance of hereditary and environmental sources of 
crime. Perhaps its most important support is the close 
agreement between his conclusions as to the importance 
of the native diathesis of criminality and other studies 
by the biometric school as to the family tendencies in 
physical traits such as stature, eye color, tuberculosis, 
insanity, and deafness. These all tend to show a correla- 
tion between parents and children or brothers and sisters 
of about .5 as compared with relations to environmental 
factors which tend to be less than .1 (165). 

(d) The criminal diathesis. 

If one accepts the point of view that the cause of crime 
is to be considered analogous to that of pulmonary tuber- 
culosis, his understanding of the etiology of crime gains 
immensely. The old question of whether the criminal 
is born or made is answered, "both." But the emphasis 
from our present data is on the inborn tendencies. More- 
over, being born with the criminal diathesis does not 
mean that a person is predestined to commit crime, but 
that he is more likely than his neighbor to be infected by 
the contagion of delinquency. We have only to catch 
the trend of recent scientific research to extend our vision 
further. The criminal does not lack a simple unit char- 
acter which would otherwise make him whole as some of 
the disciples of Mendel seem ;to argue. Neither is the 
criminal diathesis a simple instinctive tendency like the 
tendency to make a specific response to a specific stimulus, 
e. g., to wink when an object approaches the eye; the 
criminal is not charged with a specific propensity to com- 
mit murder or to steal. The safety of those who are more 
susceptible lies in keeping away from the contagion of 
bad example and temptations to fall, toward which he is 
generally less resistant than others. Specific training in 



DEFICIENCY AS A CAUSE OF DELINQUENCY 235 

strengthening and guarding his weakest spots may in 
time build up a resistance to temptations, the amount of 
which we cannot yet measure. His hope lies in the rec- 
ognition of his weakness and the adjustment of his living 
so that his whole organism may support the breach in 
his make-up during the struggle with himself and with 
society. 

In this complex diathesis which means greater suscepti- 
bility to temptations, there is little doubt that mental 
deficiency is the main factor. Aschaffenburg has well 
expressed one effect of this particular causal factor: "The 
weak-minded are generally children of the moment . . 

The lessons of experience, which serve 

normal persons as a guide, in later events, soon fade, be- 
cause they cannot be fitted into the existing condition 
of the ideas. The inability to understand, much less 
to form general points of view, is the direct result of mental 
weakness' ' (20, p. 180). Lacking the ability to organize 
their experience, fixed punishments have little restrain- 
ing influence. Only prolonged training and supervision 
can save them from being the victims of the moment. 
Even the large majority above the grade of ability which 
would justify indefinite supervision still show their stupid- 
ity in the offenses they commit. Goring gives an instance 
of a watch repairer who was legally punished nine times 
for pawning watches entrusted to him to repair. Who 
would doubt that native stupidity is an important cause 
of the recidivism which is so common a criticism of our 
present forms of legal discipline? It is stated, for example, 
that 10,000 of those convicted in one year in England had 
been convicted more than twenty times before (165, p. 
59). Even with school punishments the same association 
of bad conduct and stupidity holds. Kemsies has shown, 
as quoted by Terman, that the 16% ranking lowest in 



236 DEFICIENCY AND DELINQUENCY 

a group of pupils received 80% of the punishments, while 
the brightest third received almost none (194). 

That the criminal diathesis is not limited to mental 
deficiency is demonstrated by Goring's results. He 
shows its smaller correlation with deficient physical size, 
alcoholism and suicidal tendency with such pathological 
conditions as insanity and epilepsy, independent of their 
relations to mental deficiency. In this connection Gruhle's 
opinion that the hereditary tendency to crime was greater 
among his non-defective families may be borne in mind. 

That mental ability, and especially mental deficiency, 
is primarily a question of inherited capacity rather than 
training, is now indicated by a number of fundamental 
objective studies of the correlation of abilities within the 
family, which have been analyzed to show the relative 
influence of inborn and external factors. Among these 
studies Thorndike's investigation of the tested abilities 
of twins compared with brothers and sisters in the same 
family is the most objective, and is very convincing (199). 
He has also summarized the evidence so well that it is 
not necessary to go into the-question here (198). One of 
the most important facts is that equal practise under the 
same conditions increases the difference between indiv- 
iduals rather than makes them more alike. The work of 
the English biometricians appearing in Biometrika and 
the monographs from the Eugenics Laboratory is the 
most important in this field, and cannot be summarized 
here. It includes family resemblance in both patholog- 
ical and healthy mental traits (126). 

As compared with these studies the attempt to show 
that feeble-mindedness is inherited, because many of 
those in institutions for the feeble-minded are from fam- 
ilies showing mental taints, lacks cogency, since we are 
still uninformed as to what portion of the offspring of 



DEFICIENCY AS A CAUSE OF DELINQUENCY 237 

parents with and without deficient minds are deficient. 
Even if 85% of the children in institutions for the feeble- 
minded have tainted parents this does not mean that we 
know what percentage of deficient parents have deficient 
offspring. It is this latter fact that we must know in 
order to predict the danger of defective offspring from 
deficient parents. From what we know about the cor- 
relation of parents and offspring in mental ability, it is 
clear that the more deficient are the parents, the more 
likely it is that their offspring are deficient. Children 
of morons are, therefore, not so likely to be deficient as 
are children of parents with lower grades of ability. From 
the eugenic point of view, it is, therefore, most important 
first to protect society from propagation by the lowest 
grades of deficients, provided that all grades of deficients 
are equally likely to have children when left unrestrained 
in society. Since mental and moral qualities are prob- 
ably correlated positively, the same emphasis would be 
placed on first isolating the lowest grades in order to re- 
duce inheritance of criminality. The eugenic emphasis 
waits, however, on the discovery whether the greater 
tendency for the lowest types to be produced by the 
lowest types is overbalanced by any tendency of deficients 
or delinquents of lower degrees to be less productive 
when unrestrained in society. 

The conception of a criminal diathesis does not stop 
merely with the notion that there is an inborn predispos- 
ition to crime. It considers further that offenses do not 
occur except under the stimulus of certain situations, 
even if such stimuli may be even more common than the 
tubercle-bacillus. The important question which it now 
puts to science is, "How much may the actual outbreak 
of delinquency be reduced with better methods of social 
prophylaxis?' ' Even if, "the chief tasks of social hygiene" 



238 DEFICIENCY AND DELINQUENCY 

are the "struggle against alcohol and against poor ec- 
onomic conditions/ ' as Aschaffenburg believes {68, p. 228), 
the chief emphasis from the best scientific work still 
seems to be that the problems of alcoholism, poverty and 
crime are more closely related to internal than to the ex- 
ternal conditions which have thus far been measured. 
Guarding against the propagation of mental deficiency 
thus seems to be the most direct and hopeful method of 
attack, while the removal of infecting temptations, and 
training for greater resistance, should receive hearty, 
albeit subordinate emphasis. 



CHAPTER XII. SUMMARY AND SUGGESTIONS 

1. In our attempt to interpret the volume of results 
concerning tested delinquents, we have accepted the 
common conception that the feeble-minded are those 
who, through lack of mental development, are social de- 
ficients. They cannot survive in society without super- 
vision. In the words of the English Mental Deficiency 
Act, "they require care, supervision, and control for their 
own protection or for the protection of others." Our 
present scales of development tests do not detect those 
deficients whose failure is not directly due to intellectual 
incapacity. We have called those not detected by tests 
"purely conative cases/ ' to distinguish them from the 
tested deficients, who were said to be "intellectually de- 
ficient/ ' These conative cases would not be feeble- 
minded except for their incapacity for prolonged acts of 
will. Deficiency thus specialized in volition is so unusual, 
however, that the study of tested deficients gives us a 
useful picture of the problem of feeble-mindednsss. To 
get a general view of the relation of deficiency to delin- 
quency we determined conservative borderlines with the 
Binet scale and then reinterpreted on a common conserva- 
tive basis the results obtained in more than a score of in- 
vestigations covering thousands of objectively selected 
delinquents who had been tested. This has enabled us 
very largely to remove the question of the frequency of 
deficient delinquents from the realm of subjective opin- 
ion. We may now be certain that under present con- 
ditions the problem of deficiency is most pressing in in- 
stitutions for female offenders. The evidence also points 
to the greater frequency of deficiency among prostitutes 
and repeaters, rather than among ordinary juvenile de- 

(239) 



240 DEFICIENCY AND DELINQUENCY 

linquents. We have thus been able to restate the prob- 
lem of the deficient delinquent more conservatively and 
to modify some of the current conceptions. This enables 
us to direct our efforts more intelligently, with greater 
foresight, and more hope of success. 

2. A still broader outcome of this interpretative study 
is to increase the precision of the test scales for use in the 
diagnosis of social deficiency. This has been accomplish- 
ed by an extended reconsideration of the borderlines of 
deficiency on test scales, particularly the Binet scale. A 
percentage definition of tested deficiency is suggested for 
determining the borderline below which an individual 
may be presumed to be so deficient as to justify isolation, 
and for setting off a distance above this on the scale for 
which the test diagnosis of social deficiency should be 
regarded as uncertain. By this means it is hoped that 
the developmental scale may be made safer and more 
useful as an instrument for diagnosing feeble-mindedness. 

A quantitative definition for tested deficiency has its 
main justification in its success in discovering social de- 
ficients and in predicting social failure. With this in 
mind the percentages suggested as representing the social 
deficients or uncertain cases in the community were 
chosen after a careful search through the evidence as to 
the success of children who had been in special classes 
or institutions and an extensive resume and analysis of 
the best expert estimates of the frequency of social de- 
ficiency. The conclusion was that these percentages may 
tentatively be placed so that those who would at 15 years 
of age be in the lowest 0.5% in tested ability among a 
randomly selected group, may be presumed to be so de- 
ficient as to justify isolation. Above these the next 1.0% 
may be regarded as uncertain, since the bulk of them 
would require some supervision or guardianship during 



SUMMARY AND SUGGESTIONS 241 

life. These two borderlines have then been located on 
the Binet scale for both the immature and the mature so 
far as possible from the available data. In particular 
these borderlines for the mature have been found for the 
first time on the basis of a randomly selected group. Be- 
sides the records of Minneapolis delinquents these Binet 
borderlines for a typical random population of 643 15- 
year-olds is the main contribution of new data in the study. 

The practical consideration of these borderlines in 
Part One and their location on the test scale emphasizes 
that a test diagnosis is only symptomatic, that the sug- 
gested borderlines on the Binet scale are determined from 
limited data which may not be verified in other com- 
munities, that the scale itself is imperfect, and that the 
results should be checked by other tests, especially by 
the school retardation, a new example of which is given 
for the Minneapolis delinquents. The plan of the per- 
centage method of describing the borderlines readily 
allows for adjustment to more complete data or better 
developmental scales The alternative to the use of a 
test record as symptomatic of deficiency is dependence 
upon the history of the case or physical signs, such as are 
found among Mongolians, cretins, epileptics, etc. These 
signs have been found among only about 13% of the de- 
ficient children (141). Expert opinion given on the his- 
tory of the case is clearly less reliable than such opinion 
checked by even a crude objective test standard. In 
Part Two of this study the theoretical background for 
the percentage definition is compared with that of other 
quantitative definitions on the basis of the conceptions of 
mental measurement and mental development 

3. In attempting to suggest methods for diagnosis and 
control, which our summary of the scientific data makes 
necessary, we shall be led beyond the evidence presented 



242 DEFICIENCY AND DELINQUENCY 

in this study. To those to whom these suggestions may 
seem remoted from the foregoing pages, it may be said 
that they are the result not only of a review of the avail- 
able research work, but also an outcome of several years 
observation of the practical handling of this problem 
both in this country and abroad. In that study I was 
led to visit several scores of institutions and schools for 
delinquent or deficient children in Austria, England, 
France, Germany, Italy and Switzerland. The methods 
suggested below for the case of the deficient delinquent are 
only modifications of what has been observed in actual 
operation. 

An adequate diagnosis of deficiency involves not only 
the accurate knowledge of the present mental condition 
of the individual, but an understanding of the causes of 
that condition. This requires a complete family and 
social history of the individual and a knowledge of the 
medically removable handicaps. It would seem, there- 
fore, that such a diagnosis may be best made by a com- 
mission which shall include a physician as well as a psy- 
chologist, or else by an expert in mental development who 
is provided with adequate facilities and assistance for 
discovering other handicaps than innate incapacity. For 
the group of uncertain and conative cases a final diagnosis 
should, if possible, be made only after prolonged observa- 
tion in a temporary home school. 

Frankfurt a. M. in Germany seems to have been the 
first to provide a specialized observation cottage for un- 
certain cases among children. This was established in 
1900 and is much used by the juvenile court. Although 
it has a separate building and an isolated division of the 
grounds it is, however, connected with the local hospital 
for the insane. An improvement in this respect was made 
with the first provincial school for psychopathic children 



SUMMARY AND SUGGESTIONS 243 

under compulsory training established near Leipzig at 
Kleinmeusdorf. This serves also as a distribution sta- 
tion and has two observation divisions through which 
all fursorge children in the province pass. Only the psy- 
chopathic cases remain indefinitely. Detention homes for 
juvenile delinquents in this country quite generally are 
used for temporary quarters for cases to be observed, al- 
though these are not isolated from the other children. 
If an entirely separate observation institution is not pos- 
sible, a more definitely recognized probationary period 
for observation of the uncertain cases should be arranged 
within other institutions. The efforts for clearing-houses 
for mental defectives such as that in New York City and 
the Ohio Bureau of Juvenile Research will help to distri- 
bute individuals to their proper institutions. The ideal 
is a separate observation home where all cases in which 
the question of mental deficiency and mental disease is 
raised may be sent before the individual is labeled. The 
effect of commitment to an institution for the feeble- 
minded, insane, or delinquent can be guarded against 
much better if the observation home is entirely isolated 
from all other institutions. The separate institution, 
however, is more difficult to obtain than a separate div- 
ision or cottage in an existing institution. The latter forms 
a valuable intermediate step and is better than merely 
giving uncertain cases additional attention when other 
duties permit. 

As a matter of legal procedure, diagnosis raises the 
troublesome question of expert advice in court. Two 
decisions have to be made about each case. First, is the 
individual deficient enough to justify isolation or guard- 
ianship? Second, considering the means of care available 
in the particular community, how should the deficient be 
cared for? The first is primarily a question which re- 



244 DEFICIENCY AND DELINQUENCY 

quires expert knoweldge in mental development and should 
be so handled. The second decision requires knowledge 
about the individual's home and about the facilities for 
guardianship or isolation. It should be left with the 
authorities thus informed. This will usually be the court 
unless there is a commissioner or a committee especially 
charged with this duty. 

An important advance in the legal definition of criminal 
responsibility of deficients should be made by avoiding 
all subtle questions of psychological analysis such as 
would be involved in deciding, for example, under the New 
York statute whether the accused "was laboring under 
such a defect of reason as not to know the nature and 
quality of the act he was doing or know the nature of the 
act as wrong." Obsolete legal descriptions could easily 
be cleared away by adopting the statement of the law 
suggested by the Committee of the Institute of Criminal 
Law and Criminology for criminal responsibility and in- 
sanity. In substance such a law would then state that the 
accused was mentally deficient "so as not to be respon- 
sible ... for his acts or omissions at the time when 
the act or omission charged was made." The New York 
law places an emphasis on knowledge which should be 
placed on will, only one feature of which is an understand- 
ing of the situation. 

4. What should be the aim in the care and control of 
deficients and delinquents after diagnosis also depends 
upon a proper understanding of the causes of these con- 
ditions. We have summarized some of the best and most 
recent investigations in which a notable advance toward 
solving this problem has been made by means of the cor- 
relation method. This has proved to be a new and vig- 
orous force for directing social progress. By no other 
method have we approached so near the solution of the 



SUMMARY AND SUGGESTIONS 245 

cause of delinquency. It enables us to restate the problem 
of criminality as mainly a problem in the treatment of a 
hereditary criminal diathesis in which mental deficiency 
is the largest factor. These recent scientific measure- 
ments have deprived neither the eugenist nor the euthenist 
of the opportunity for service. There is plenty of con- 
genial work to be done by those whose sympathies may 
exaggerate the influence of heredity, contagion, or train- 
ing. As in the control of tuberculosis, so with the dia- 
thesis of delinquency, some effect is produced by predis- 
position, by training, and by external influences. Unless 
the present evidence, however, is outweighed by improved 
data obtained in the future, the most strategic point for 
attacking persistent delinquency is through the relation 
to deficiency, with heredity holding the heights. 

With the immediate campaign against delinquency 
centered against the propagation of the social deficients, 
we have the atmosphere cleared so that it is possible to 
turn attention to the best means of attaining this end. 
Sterilization, isolation, or guardianship, by force or by con- 
sent, which of these methods promises best? This is 
not a question for detailed discussion here. We may, 
however, call attention to the strides that have been made 
by such legislation as the British Mental Deficiency Act 
of 1913 and to the summary of the laws of the several 
states in our country published at the University of 
Washington, Seattle. The question whether steriliza- 
tion is desirable must at present be settled apparently 
by the judgment whether the benefit in reducing the 
propagation of the unfit outweighs the danger to morality 
through the temptation of known sterility. The question 
of isolation of the sexes by either sterilization or segre- 
gation resolves itself into the question of accuracy of diag- 
nosis and prognosis. Our review of the uncertainties of 



246 DEFICIENCY AND DELINUENCY 

diagnosis should make us cautious. When we consider 
the social survival of many of those trained in the public 
school classes for deficients and when a dozen girls dis- 
charged from the Massachusetts institution for the feeble- 
minded succeeded in getting along in society {164, p. 49), 
it would seem wise to place the emphasis on first isolating 
those about whose danger to the community through 
delinquency or propagation of deficiency there would be 
the least question. This would mean those of uncertain 
mentality who were already repeated delinquents or in 
imminent danger and those who were of the lowest grades 
of deficiency, not the morons who were of uncertain 
moral and mental ability. Among the clearly deficient 
there is no question but that the emphasis should be to 
isolate first the girls and women of child-bearing age, since 
their chance of obtaining mates is greater than that of 
the deficient males. With doubtful cases public guard- 
ianship, such as that provided by the British Mental 
Deficiency Act of 1913, affords a promising remedy. 
Even those who are of uncertain ability should, when in 
danger, be provided with whatever protection guardian- 
ship can give. In this connection a suggestion of Dr. 
Goddard in the Survey, March 2, 1912, may be utilized. 
A court in returning an individual who is of uncertain 
ability to his family or guardian may well warn them: 
4 'We shall leave him in your custody, but we insist that 
you shall care for him, shall be responsible for him through- 
out his life, shall see that he does not get into mischief, 
and above all that he does not become a parent. When- 
ever the time comes that we find you are incapable of 
performing or are neglecting this duty, then we shall 
take him and place him in a colony." 

The question where to isolate the deficient delinquent, 
whom Kuhlmann says is "equally well placed or mis- 



SUMMARY AND SUGGESTIONS 247 

placed in the institution for the feeble-minded and the re- 
formatory/ ' (140) is answered in substance by Supt. 
Murdoch of the State Institution for the Feeble-Minded 
in Western Pennsylvania. He suggests that in large 
states the deficient delinquents might be cared for in an 
institution which should bear the same relation to the 
state institutions for the feeble-minded and the penal in- 
stitutions as is now held by the asylums for the criminal 
insane. Where a separate institution is not possible the 
affiliation with the institutions for either the delinquents 
or the deficients may be tried by means of colonies es- 
pecially set apart in them. In Massachusetts these divis- 
ions for the deficient delinquent are connected with the 
institutions for delinquents. 

5. Turning to external influences upon delinquency, 
we find that their effect has been measured mainly in 
connection with the tendency to repeat criminal acts. 
It has been shown by Goring that even such important 
influences as the example of criminality in the home, 
kind and amount of schooling, irregularity of employ- 
ment, alcoholism, size of family, low standard of living, 
early death of mother, etc., have generally been found not 
to increase notably the tendency to recidivism while they 
do correlate decidedly with deficiency. Nevertheless, it 
has not been determined whether these external factors 
may not have an important influence upon the first mani- 
festation of the criminal diathesis even though they tend 
only slightly to increase recidivism. Should these ex- 
ternal influences prove to be not more than a fifth as im- 
portant as deficiency and heredity, which now seems to 
be indicated, we need to hunt for other outer influences 
which may really prove to be more important. 

Among bad external influences as yet unmeasured is 
maladjustment to school among those of passable ability. 



248 DEFICIENCY AND DELINQUENCY 

We have given some evidence as to this which we found 
among a group of delinquent boys at a county farm 
school, when their test records were compared with their 
positions in school. As a possible serious source of de- 
linquency, bad adjustment to school work should be stud- 
ied further, since it is a matter that could be easily cor- 
rected by the assistance of special teachers. With the 
earlier discovery of deficient children by means of mental 
tests, it should also be possible more definitely to direct 
the training so as to build up resistance to worldly temp- 
tations. How much could be done in this direction we 
cannot yet say. We have undoubtedly wasted much 
effort in the past in trying to create intellectual capacity 
in those who are innately deficient in intellect. Fortun- 
ately we are now directing our attention to training them 
to acquire passable ability in simple occupations, or to 
adjust themselves to the life of a colony. In the edu- 
cation of the mentally weak the most promising field is 
undoubtedly with the conative cases with passable in- 
tellects. At Templin, outside of Berlin, there has been 
established the first home school devoted entirely to the 
training of such unstable and inert boys. This specialized 
institution for conative cases, which was founded by a 
philanthropic society at the suggestion of Prof. Thiedor 
Ziehen, marks a most important advance step in the prob- 
lem of training the mentally deficient. The results of 
specific training for the social adjustment of the intellect- 
ually and of the volitionally deficient will be awaited with 
great interest. 

6. Shall the public authorities have the power to com- 
pel isolation and special training at local or state schools? 
These powers have already been provided by laws in a 
number of states. Thus far the law has not outstripped 
scientific knowledge. How far the authorities should 



SUMMARY AND SUGGESTIONS 249 

use their discretion under these laws to force isolation is 
a question which calls for the utmost good judgment on 
their part. In case the parents or guardians of the socially 
deficient can be convinced of the desirability of such iso- 
lation, this procedure is undoubtedly to be urged. When 
the guardian has once consented to the isolation of his 
charge, he should not be permitted to remove the in- 
dividual from such care without the consent of the proper 
public authority, which would of course be reviewable in 
court. During this period of uncertainty as to the prog- 
nosis of social deficiency, such a procedure would perhaps 
be preferable to forced isolation in most cases, since the 
authorities might be less troubled by the frequent an- 
noyance of legal actions begun by parents who had their 
children forcibly removed to institutions. In some states 
unscrupulous attorneys have deliberately stirred up par- 
ents to try to get back their children who had been taken 
away by force, thus seriously interfering with the adminis- 
tration of laws for compulsory isolation. Without the 
possibility of compulsory isolation of the socially deficient 
for an indefinite time, we shall perpetuate the disgraceful 
spectacle now observable in many states which cannot 
legally prevent a feeble-minded parent removing a feeble- 
minded girl from an institution to which she may be brought 
back a few years later with one or more illegitimate, feeble- 
minded children. Our legal omissions should not thus 
handicap the wisdom of society. The 1917 codification 
of the Minnesota laws relating to defective, delinquent 
and deficient children should be seen by those who are 
interested in the legal aspects of these questions. It was 
brought about by the Minnesota Child Welfare Com- 
mission, of which Judge Edward F. Waite was chairman. 
7. In case we suddenly segregate for life all those who 
are so deficient that we are justified in isolating them, 



250 DEFICIENCY AND DELINQUENCY 

would that solve the problem of delinquency for the next 
generation? Although this would be the most important 
attack which could be made on the most important known 
cause of delinquency, we must still answer that the re- 
sults would hardly be comparable with a jail delivery. 
There is nothing to be gained by turning our backs upon 
the facts. Goring has estimated that 7.2% of the male 
population of England and Wales commit crime before 
death. We could not possibly suppose that more than 
1% of the male population could be justly isolated for de- 
ficiency. Even if all the deficients committed crime, at 
least six-sevenths of the criminals in these countries, 
about which we have the best means of estimating, are 
presumably individuals who could not be isolated for 
deficiency. 

Moreover, Goring's estimates regarding the British 
convicts enable us to judge that only about 25% of the 
criminals of this generation inherit a predisposition to 
crime from parents who were the criminals of the last 
generation (20, p. 336). Nobody has suggested isolating 
all persistent delinquents. We could not expect that the 
isolation of both the deficients and delinquents would 
completely remove the diathesis of delinquency from 
society. The predisposition is received not only from 
the deficients and delinquents, but also to some extent 
from those above the borderlines. We could not raise 
the borderlines of deficiency without isolating many 
whose social deficiency or delinquency it would be pre- 
sumptuous to predict. We should not look forward, 
therefore, to the sudden elimination of the problem of 
delinquency even when it is attacked at its most vital 
spot. On the other hand Dr. Hart, in a bulletin of the 
Russell Sage Foundation, has worked out a practical plan 
which would isolate the lowest 0.3% of the girls and wo- 



SUMMARY AND SUGGESTIONS 251 

men of child-bearing age in this country within five to 
ten years. Some similar plan for isolating all deficient de- 
linquents would materially lessen the cost of recidivism 
in the present generation. 

The most hopeful sign is that we are no longer content 
merely to guess at the relative importance of the sources 
of delinquency and deficiency, but our efforts to promote 
social welfare are directed by scientific investigations 
which are utilizing new and more efficient methods of 
research. 



PART TWO 
THEORETICAL CONSIDERATIONS 

CHAPTER XIII. THE THEORY OF THE 

MEASUREMENT OF MENTAL 

DEVELOPMENT 

In defining the borderline of feeble-mindedness it will 
be found that certain assumptions are usually tacitly 
made as to the form of the curves of normal and retarded 
development. These assumptions which are often based 
on vague conceptions of mental measurements should be 
brought clearly to mind if we are to compare the relative 
merits of different scales of mental tests or different ways 
of stating the borderlines of deficiency. With this in 
view it is proposed to take up in this second part of the 
monograph a brief technical discussion of the units of 
mental measurement, the equivalent individual differ- 
ences at different ages, and the curves of mental develop- 
ment. The bearing of these conceptions on the various 
quantitative definitions of tested deficiency, including 
the percentage definition, will then be discussed in the 
following chapter. Practical advice as to individual 
diagnosis or group comparisons has been confined to 
Part One, so that those who are not concerned with the 
theoretical assumptions on which the conception of mental 
development and the interpretations of tested deficiency 
are based should omit Part Two. 

When we try to picture to ourselves the significance of 
individual differences and mental development we are at 
once forced to think in terms of graphs showing the dis- 
tribution of abilities at particular periods of life and the 

(252) 



MEASUREMENT OF MENTAL DEVELOPMENT 



253 



Objective Units 



^ ^ (ft Oi 
O Oi O Ch 




^ Ot Ot 
Oi O Cft 



254 DEFICIENCY AND DELINQUENCY 

changes from one life-age to another. To simplify the 
discussion I have presented in Fig. 3 the graphic picture 
of the conditions on the simplest hypothesis, namely, 
that mental capacity at each age is distributed in the 
form of the normal probability curve extending to zero 
ability and that individuals retain their same relative 
capacity on the scale of objective units. 

A. Comparison of Units and Scales for Measur- 
ing Individual Differences. 

(a) equivalent units of ability when the distri- 
butions ARE NORMAL. 

In considering the curves of development it is desirable 
first to notice the differences between measurement in 
equal physical units and measurement in equivalent units 
of ability or of development. The difference in the point 
of view of the two forms of measurement is so pronounced 
that I can hardly hope to make myself clear to those who 
are not somewhat familiar with such terms as "distribu- 
tion curves," "frequency surfaces," "standard deviation," 
and other phrases connected with the theory of probabil- 
ity, which are treated at length in such books as Thorn- 
dike's "Mental and Social Measurements" and Yule's 
"Introduction to the Theory of Statistics." We often, 
by mistake, regard the growth of an inch in height, for 
example, as always representing an equivalent unit of 
growth. This will lead us into rather serious misconcep- 
tions unless we are careful, for it is perfectly evident 
that the growth of an inch in height has a very different 
significance for the three-year-old boy than for the eight- 
year-old. Half of the three-year-old boys grow about 3 
inches during a year while at eight years of age not more 
than about one in seven grow that much. Moreover it 



MEASUREMENT OF MENTAL DEVELOPMENT 255 

is not always satisfactory to regard the same relative in- 
crease in physical size as an equivalent unit of develop- 
ment. To say that a boy 20 inches tall who grows 1-10 
in height shows an increase in development equivalent to 
a boy of 50 inches who grows one-tenth, may be quite 
misleading. Nearly every 20-inch child grows one-tenth in 
height in a year while not one in fourteen of the boys 
who are 50 inches in height may grow at that physical 
rate. In considering human traits, and especially de- 
velopmental traits, it would seem to conduce to more 
significant thought if we gave up at times our habit of 
thinking in terms of equal or relative physical units and 
thought instead in terms of more equivalent biological 
units. 

In the measurement of mental ability, moreover, it is 
exceedingly difficult to utilize equal physical units. Most 
of the objective units which are commonly called alike 
are clearly not equal even in the physical sense. "Spelling 
one word," for example, is not equal to spelling another 
"one word;" but only equal to spelling the same word. 
Out of such units of amount accomplished, it is, of course, 
not possible to build a satisfactory scale without referring 
to some other concepts of measurement. Some tests, 
however, are scored in equal units. When the measure- 
ments for example, are in the units of time it takes to 
perform the same task under the same outward conditions 
we have the possibility of a scale of equal objective units. 
Such a scale is approached by the results with the form 
board test which give the number of seconds it takes chil- 
dren to place blocks of different shapes in their proper 
openings. 

Even the unit of time may be deceptive in name, as 
it is with the Binet scale. A year of time is, of course, 
the same physical unit and the task proposed with the 



256 DEFICIENCY AND DELINQUENCY 

Binet scale is always the same, but the other essential with 
this scale, the children of each age who pass the tests at 
each age norm, varies decidedly. "Test-age five," for 
example, means 44% of the children pass and "test-age 
eleven" means 88% pass, even with approximately ran- 
dom samples of children of these life-ages. This question 
of the equality of the Binet age units will have to be con- 
sidered further, therefore, in connection with the other 
concept of equivalence used in psychology. 

In order to determine equivalent units of activity we 
find that a number of different concepts have been utilized. 
With some of the scales for measuring educational pro- 
ducts, such as Thorndike's Scale for Handwriting, equal 
units of merit in handwriting mean differences judged equal 
by relatively the same proportion of competent judges. 
This form of unit has not been used, however, in any 
scale of mental development thus far proposed. 

In the measurement of mental ability the most com- 
monly accepted idea of equivalent units is that they are 
provided by the units of standard deivation for a series of 
measurements which distribute in the normal form. The 
meaning of these units may be understood by referring to 
Fig. 3 which shows Gaussian or normal distributions of 
abilities of individuals at various periods of life in curves 
A, B, C, D and E. The straight lines of the measurement 
scales form the bases of these distribution curves. These 
graphs represent the normal form of distribution usually 
expected when any fundamental ability is measured in a 
random group. If the number of cases at each unit of 
measurement are plotted by a point placed relatively as 
far above the scale, used as a base line, as the number of 
cases found at that unit of the scale, it will be discovered 
that these points arrange themselves in the form of a 
symmetrical curve high at the middle and flaring out 



MEASUREMENT OF MENTAL DEVELOPMENT 257 

along the base-line scale. This bell-shaped curve, known 
as a normal probability curve, shows that the largest num- 
ber of cases occurs at the middle or average measurement. 
From this middle point on the scale the number of cases 
falls off gradually and symmetrically in both directions. 
Distances along the base line of this distribution surface 
may then be measured in terms of the standard deviation 
regarded as unity. This S. D. is the best measure of the 
scatter of the deviations. It is the square root of the 
average of the squares of the deviations of the separate 
measurements from the average of all the measurements. 
There are approximately four units of the standard de- 
viation between the average and either extreme when the 
distribution is normal, as in Fig. 3. Only six cases in one 
hundred thousand fall outside these limits. 

The studies of biological traits suggest that a unit of the 
standard deviation is the most important measure we 
have for equivalent degrees of any trait which distributes 
normally. It measures the same portion of the total dis- 
tance from the lowest to the highest ability on any ob- 
jective scale so long as the distribution of measurements is 
in the normal form. It thus affords the best interchange- 
able unit from measurements at one life-age to those at 
another, provided that the distributions keep close to the 
form of the normal probability curve. This is the as- 
sumption on which practically all the developmental 
scales have been based. The difference in ability be- 
tween an individual at the average and at -1 S. D. (stand- 
ard deviation) below the average is equivalent to that 
between the last individual and one at -2 S. D. The 
same distances along the base line of different distribu- 
tion surfaces measured in terms of their respective devi- 
ations set off equivalent portions at each age so long as 
the distributions are normal. For example individuals 



258 DEFICIENCY AND DELINQUENCY 

measuring between -2 and -3 S. D. in any distribution in 
Fig. 3 are equivalent in ability to those lying between -2 
and -3 S. D. in any other of these normal distribution 
surfaces. Later we shall consider equivalent units when 
the form of the distribution of ability is not normal or is 
unknown. 

We may now compare the relations of the units in the 
physical scale, shown at the left of the figure, to units 
of the scales for adults or for the immature of any age, 
expressed in units of the standard deviation from the av- 
erages of these groups. Relative ability measured on 
the physical scale or any one of the distribution scales in 
Fig. 3 will be found identical since they all start from the 
same zero point and the distributions are all normal. But 
the ability of an individual in one distribution can hardly 
be compared with that of an individual in another dis- 
tribution in a biologically significant way by their ac- 
tual positions on the physical scale. A physical unit, 
does not measure the same sort of fact of development in 
a scale for the immature that it measures- in the scale for 
adults or that it measures in another dynamic scale for 
the immature. This can be seen when a physical unit is 
compared with the amount of standard deviation which it 
measures in the different scales. Moreover, the corres- 
pondence of relative distances on the physical scale and 
any one of these other scales will not hold the moment 
the distributions do not start from the same point or are 
unsymmetrical. 

It does not seem seriously wrong to suppose that there 
are some individuals at any age who have no more mental 
ability than the baby of the poorest mental ability at 
birth. At any rate our intelligence scales are hardly fine 
enough to measure the difference in intellectual capacity 
between the dullest adult idiots and the dullest idiot 



MEASUREMENT OF MENTAL DEVELOPMENT 259 

babies. We shall, therefore, here assume that mental 
capacity extends to zero at each age. The importance 
of this will be evident when we consider the question 
whether the distributions of ability are symmetrical 
around the average point at each age. Postponing for the 
present the discussion of unsymmetrical or skewed distribu- 
tions, we may consider the several meanings of stages of 
development. 

In applying the concept of the probability curve we 
should distinguish between individuals who have attained 
their mature mental capacity and those who are still 
maturing. The former would be represented by a random 
group of adults (Distribution E, Fig. 3) the latter by a 
group of nine-year-olds (Distribution C). If we say, for 
example, that a child has reached a certain stage of de- 
velopment we might have in mind the final distribution ot 
mature capacity or the distribution of capacity among 
those of his particular age or of all ages. When we com- 
pare stages of development we must, therefore, be careful 
to indicate the distribution surface to which we are re- 
ferring. 

An increase in development may refer to at least five 
different things depending upon the scale of measurement 
to which reference is made. Besides an increase measured 
by the physical scale, the scales for adults, for the immature 
or for all ages, to which we have already referred, it may 
mean an increase judged by the distribution of increases 
which individuals of the same life-age and capacity make 
in the same period of time. This last meaning may be 
the most significant, although it has never been used. It 
has reference to a distribution surface of increases such 
as is represented in Distribution F, Fig. 3. This is intend- 
ed to show the increases in one year of all two-year-old 
children who had average ability at 2 years, on the as- 



260 DEFICIENCY AND DELINQUENCY 

sumption that at 3 years these children would on the 
average equal the average of all three-year-olds. It is 
clear that when these increases are measured in objective 
units the latter have a still different significance from 
that assigned to, them in connection with other scales. 
An increase of one objective unit here might represent 
twice the standard deviation, while it only represents 0.2 
of the standard deviation in another distribution. 

(b) THE YEAR UNIT OF THE BINET SCALE. 

A sharp disagreement of opinion as to whether the 
Binet year units can be regarded equivalent has arisen 
between Karl Pearson, Director of the Galton Laboratory 
in London, and certain psychologists who have used the 
Binet scale. Cyril Burt, for example, says, as quoted by 
Pearson: 

1 'Except for rough and popular purposes, any measure- 
ment of mental capacity in terms of age is unsatisfactory 

The unit fluctuates in its 

significance all along the scale. When the child is just 
beginning to walk and talk, when he is 7 or 8, when he is 
10 to 11, when he is on the verge of puberty — at these 
different periods a retardation of a single year means very 
different things" (164, p. 36). 

A number of good psychologists including Yerkes, Ter- 
man, and Kuhlmann, agree with Burt in maintaining that 
a year of retardation at different ages has very different 
significance. 

With this statement of Burt, Pearson takes issue, say- 
ing: 

"Can the psychologist to the London County Council 
ever have seen the growth curves of children, or would he 

write thus? There is no valid reason 

to suppose that a year's growth in mental power may not 



MEASUREMENT OF MENTAL DEVELOPMENT 261 

be taken for all practical purposes to mean the same unit 
for ages of 6 to 15, the period for which Binet and Jaeder- 
holm have used the tests" (164, p. 44). 

Like many other apparently opposite statements both 
contain truth. The conflict arises apparently, first from 
a disagreement between the data obtained with the Jaeder- 
holm form of the scale, on which Pearson bases his state- 
ment, and data obtained with other forms of the scale; 
second, from a discrepancy in the points of view. Pear- 
son stresses the fact that the mental year-marks equal 
average growth increment with the Jaederholm scale (167). 
He shows that the regression of years of mental excess 
(or deficiency) on increase of life-age is a straight line, 
just as he found it with physical measurements. More- 
over, the standard deviation of the mental measurements 
for the entire group of normal school children, 6-14 years 
of age, was found to be about one year of mental age (.96 
year for the corrected data) (167). To which Pearson's 
opponents might reply, these facts are of comparatively 
little significance unless the deviations for the separate 
ages are alike in terms of these year units on the scale. 
Neither linear regression nor the balancing of years of 
excess by years of deficiency at each age indicates that the 
deviations of the separate ages are alike in terms of the 
year units. The new Stanford scale, for example, shows 
both of these conditions and yet the range of months of 
life-ages which sets off the middle 50% of the children of 
the different tested ages increased decidedly from 6 to 14 
years of age. The middle half of the tested ages, for ex- 
ample, at age VI on the scale include a randomly selected 
group of six-year-old children whose range of life-age is 
ten months, at age VIII on the scale this range is 13.4 
months, at X it is 16 months, at XII, 20 months, and at 
XIV, 26 months. 'The number of 6-year-old children 



262 DEFICIENCY AND DELINQUENCY 

testing 'at age' is approximately twice as great as the 
number of 12 year-olds testing at age, and 50% greater 
than in the case of the 9-year-olds" (196, p. 557). 

To this argument Pearson might reply that he had not 
overlooked the question of variation in the deviations 
from one age to the next for he has a footnote in which 
he states regarding the Jaederholm data: 'There are, 
however, relatively little differences in these mental age 
standard-deviations of the normal children beyond what 
we may attribute to the effect of random sampling" (164, 
p. 46). In this respect, then, the Jaederholm data differ 
notably from Terman's data obtained with random groups 
with the Stanford scale and, as I shall show, from data 
obtained by Goddard with the 1908 Binet scale, the two 
largest groups of Binet test data which have been collected. 
Even with the Jaedeholm data on efficient school chil- 
dren, although the largest difference between the standard 
deviations of different age groups is only about twice its 
probable error, it is notable that 24 of his 39 7-year-olds 
are included within an interval of the middle year of 
tested age, while only 9 of his 35 11-year-olds are included 
within the same middle year interval. 

Taking Goddard's data for the 1908 scale for the sep- 
arate ages from 5-11 at which probably the factor of selec- 
tion for his groups may be neglected, I have calculated 
the standard deviations from his Table I and find them 
as follows: 



Standard deviations in 


Life-Ages 


Mental Excess or De- 


5 
1.10 


6 


7 


8 


9 


10 


11 


ficiency 


.98 


.93 


.99 


1.04 


1.23 


1.19 



The differences between the deviations for ages 7 and 
11 or between ages 8 and 10, are more than three times 
their standard errors, so that we would not be justified 



MEASUREMENT OF MENTAL DEVELOPMENT 263 

in assuming that the standard deviations of the separate 
ages measured in terms of years of excess are equivalent. 
There seems to be a tendency for the deviations to increase, 
at least from age 7 to 10 and 11. 

The comparison of the year units on the Binet scale 
with the diagrams in Fig. 3 shows that if the scale at each 
life-age shut out the same lowest proportion, say half, of 
the children of that age, then the year units might be 
regarded as equal in the sense of equal average growth 
increments, as Pearson suggests. A child 7 years of age 
testing VII would be at least one annual average-growth 
unit higher in mental development than one of 6 years 
testing VI, and so with each age until the limit of develop- 
ment had been reached. This is the condition approxi- 
mated closely for children by the new Stanford scale and 
the corrected Jaederholm data. Since there is little pros- 
pect, however, even with a scale perfected so far as its 
age norms are concerned, that the total distributions for 
each of the different years would be the same multiple 
of the year-units, the main significance of the age units is 
in permitting the statement that a child had reached the 
tested development normal for the children of a certain 
age. 

It is also legitimate to use years of retardation as a 
short way of expressing rough borderlines when they hap- 
pen thus to afford an easy method of empirically describ- 
ing equivalent borderlines for a particular scale. This 
is what I have done for convenience in Part One of this 
book. I certainly do not mean to contend that four-years 
retardation has theoretically the same significance at dif- 
ferent ages, in terms of the deviation of the separate ages. 
To me the Binet years are no more than names for certain 
positions on the scale. 

To most psychologists who have been dealing with the 



264 DEFICIENCY AND DELINQUENCY 

measurement of mental development, I believe that the 
most significant concept of equivalent units would be in 
terms of the deviations for each age provided that the 
form of the distributions remained normal. But the de- 
viations vary so much in the terms of the year units that 
it is not likely that they will be willing to accept a year 
of excess or deficiency as an equivalent unit for different 
ages with the common forms of the scale in use in English- 
speaking countries. Moreover, below the age of 6 and 
above 15, the limits which Pearson discusses, there is 
good reason to expect the year unit to vary still further. 
This Pearson recognizes for the complete developmental 
curve. It is only at the intermediate years, in which the 
average increases are most constant in relation to the de- 
viations of the separate ages, that the year unit may be 
at all serviceable in measuring the deviation of a child 
from the norm of his age. 

With the scales in use in this country the Binet year 
units are not equivalent in the sense in which they are 
usually spoken of as equivalent. We should recognize 
this and emphasize it. Even if the norms at each age 
marked off the same proportion of the individuals, as 
shown in A and B of Fig. 4, unless we knew that the 
forms of distribution were always alike, we should not 
know that the distance between successive age norms was 
the same on any sort of objective scale other than aver- 
age age increments. Moreover, we would not have an 
objective scale of equal units applicable to measuring the 
deviation of children of any one age. The average an- 
nual increments would not necessarily represent the same 
proportion of the total distance from the lowest to the 
highest ability at different ages even if the distributions 
were all normal. With normal distributions it would also 
be necessary to demonstrate empirically that the annual 



MEASUREMENT OF MENTAL DEVELOPMENT 



265 



ft 
(0 





rt» 


ii 


s 


«4 


1 


u* 




^ 



,* 









^ 
1 



s 



(0 



CO 





266 DEFICIENCY AND DELINQUENCY 

average growth increment between successive ages always 
bore a constant relation to the deviations at these adja- 
cent ages as shown in B of Fig. 4 where the increment is 
equal to 1 S. D. at each age. This could not possibly 
hold when the increment lessened near maturity. 

If the distributons of ability were variously skewed, the 
year units of excess or deficiency would not be shown to 
be equivalent at the different ages even if the proportion 
of individuals one year accelerated was equal to the num- 
ber one year retarded, two years accelerated equal to those 
two years retarded, etc., at each age and the norm at each 
age shut out the same proportions of the age group. This 
is shown in C of Fig. 4 in whch the year units are clearly 
not equal steps from lowest to highest ability even for the 
same age and yet the usual criteria which have been sug- 
gested for discovering the equivalence of the units are ful- 
filled. Whether the actual distribution of ability is 
skewed or normal cannot be determined by the Binet 
scale, of course, on account of the uncertain and probably 
varying size of its year units in measuring deviations at 
any age. 

With the empirical evidence against the equivalence of 
the year units and the impossibility of determining their 
equivalence unless we first know that ability is distributed 
normally at each age, it is certainly hazardous to assume 
that individual deviations measured in terms of year units 
are equivalent at different ages. 

It may be noted that it is quite as hazardous to suppose 
that the units of the Point scale are equivalent in any 
theoretical or practical sense. This question will be dis- 
cussed later in Chap. XIII, B, (b). 



MEASUREMENT OF MENTAL DEVELOPMENT 267 

(C) IS TESTED CAPACITY DISTRIBUTED NORMALLY? 

Before leaving the question of the significance of units 
on a scale described in terms of the standard deviation 
we should ask whether tested mental abilities have been 
found to distribute normally, L e., in the form of the sym- 
metrical Gaussian curve with each extreme the same dis- 
tance from the middle measurement. Contrary to the 
usual supposition in this matter, it seems as if the evidence 
was somewhat against this assumption, although neither 
position can be asserted at all dogmatically on the basis 
of our present data. A resume of this evidence which I 
have given below makes it appear that the assumption 
of a normal distribution will not conflict with a practical 
use of normal probability tables for medium degrees of 
ability, but may quite seriously interfere with such use for 
the borderline of deficiency. There is little doubt, as 
Pearson believes, that the bulk of the children now in 
special classes for the retarded in the public schools would 
fall within the lower range of a normal distribution fitted 
to the general population. On the other hand, there is 
likely to be a respectable minority of the deficients which 
will be beyond such a normal curve. These facts are 
sufficiently evident, I believe, to make it impossible to 
base quantative descriptions of borderline of deficiency 
on a hypothesis of normal distribution. 

The best evidence on this point is probably the data of 
Norsworthy with eleven tests on groups of 100 to 150 
feeble-minded children in institutions and special classes 
and 250 to 900 normal children. She expressed the posi- 
tion of each child in terms of the deviation of the group 
of normal children of his age for each test. Pearson has 
presented her data graphically on the assumption that her 
defective group represented 0.3% of a general population 



268 DEFICIENCY AND DELINQUENCY 

of 50,000 children, and then fitted a normal distribution 
curve to her data with her normal group. The result 
makes it evident, especially for the intelligence tests, that 
the defective group would better be described as part of a 
skewed distribution. To less extent this is also true for 
the maturity and memory tests (15, p. 30). Norsworthy's 
own table of data show that 43 of the 74 feeble-minded 
taking the intelligence tests were over - 5 times the probable 
error of their ages below the averages of the normal chil- 
dren, a criterion which she proposes as indicating ability 
outside of that included in the normal species. Moreover, 
9 children score between -22 P. E. and -32 P. E. which 
is far beyond any conceivable extension of the normal 
curve. Her figure for the composite results of all her 
mental tests is also manifestly skewed toward deficiency 
although she hesitates to adopt this conclusion, and was 
content with showing that they grade off into the distri- 
bution of normal children. 

The other data, which I have found, that indicate that 
tested ability, when measured in equal physical units for 
the same task, is skewed toward deficiency, have to do 
with tests that are pre-eminently for psychomotor activ- 
ities rather than intellectual. They consist of Sylvester's 
and Young's results with the form board test on Philadel- 
phia school children, Stenquist's results with his construc- 
tion test, and Smedley's results with the ergograph test on 
Chicago school children. Here we may apply the better 
criterion of the distance of the quartiles above and below 
the median of the group. These positions would be less 
likely, through extreme records, to be affected by chance 
conditions during the testing. 

It is to be remembered that if the records of school pu- 
pils appear to be normally distributed this would not settle 
our problem, since it is apparent that idiots and many 



MEASUREMENT OF MENTAL DEVELOPMENT 269 

imbeciles are not sent to the public schools at all. The 
lowest children at any age would not be represented in 
the regular school groups. On the other hand, the bright- 
est children are not generally drawn away from the public 
schools at least before 14 years of age in this country. We 
shall confine ourselves, therefore, to school-children 6-13 
years of age. If we find that they show ability skewed 
toward deficiency the results will under-estimate rather 
than over-estimate the skewness. 

Sylvester (191) tested with the form board a group of 
1537 children in the Philadelphia public schools, from 80 
to 221 at each age from 5 to 14 inclusive. "Except that 
no especially backward or peculiar children were included 
there was no selection/ ' This study gives, with the com- 
plete distribution tables, the number of seconds required 
for the same task by the children at each age. If we 
find that the limit of the lower 25 percentile was farther 
from the median than the limit of the upper 25 per- 
centile we can be reasonably sure that the difference 
would be still greater if the excluded deficient and back- 
ward children were also included. By calculating the 
quartiles and their differences from the medians at each 
age, I find that for only two of the eight ages is the upper 
quartile farther from the median than the lower quartile. 
The average excess of the distances of the lower quartile 
is .64 of a second. At only age 7 is the difference three 
times its probable error, 2.1 seconds, P. E. .67. The form 
board distributions thus tend to be slightly skewed toward 
deficiency. The errors of the quartiles were found by 
the method given in Yule's Introduction to the Theory of 
Statistics, Chap. XVII, which assumes normal distribu- 
tion, so that they are too small. The skewness is more 
manifest when the extreme measurements are compared 
with medians at each age. It is not possible, unfortunately, 



270 DEFICIENCY AND DELINQUENCY 

to compare his group of normal children with those in the 
special classes since he did not use the same method of 
giving the test. 

Since it was not important to compare the amounts of 
skewness in different data, I have not attempted the more 
elaborate calculations of coefficients of skewness. These 
would give the results a more elegant statistical expres- 
sion. The simpler method I have here used affords more 
convincing evidence of asymmetry for the non-mathe- 
matical reader. 

Young has published the results with Witmer's form 
board test on approximately two hundred Philadelphia 
children for each age, giving the results for the sexes sep- 
arately for each half year of life-age (227). This affords 
36 different groups in which he gives the median and 
upper and lower quintiles for the shortest time records. 
The lowest quintile is farther from the median in 25 cases, 
equal in 6 and less than the upper quintile in only 6 of the 
36 comparisons. This skewness would have been even 
greater if children of the special classes had not been ex- 
cluded from his groups. 

Stenquist's results (54) with his construction test are 
scored in arbitrary units in which allowance is made for 
the quality of the score, but we should expect no constant 
effect on the form of the distribution from the character 
of these units of measurement. At ages 6 to 13 he tested 
from 27 to 74 pupils randomly selected from the public 
schools, a total of over 400. For six of these eight ages 
the lower quartile is farther from the median than the 
upper quartile, when calculated from his distribution 
table. The number of cases at each age, however, is so 
small that the largest difference, 15 units, is not three 
times its probable error, 6. 



MEASUREMENT OF MENTAL DEVELOPMENT 271 

Smedley gave his ergograph test to about 700 school 
children of each of the ages we are considering. Since 
he tested so many more subjects than any other investiga- 
tor this should provide the most valuable data on the 
question of distribution with a test recorded in the same 
physical units for the same task. Unfortunately, his re- 
sults for two succeeding years are so directly contradictory 
to each other that they seem to have no significance 
for our problem. The simplest explanation of this con- 
tradiction is that the groups tested may have been selected 
on a different basis each year. 

A casual observation of his standard percentile curves for the ergo- 
graph test at the different ages gives the impression that the distribu- 
tions are decidedly skewed toward deficiency, but this impression is 
not justified by a careful analysis of his results (51). In the table 
which accompanies his standard percentile curves, giving his total 
results for the two years, we find that there is a sharp disagreement 
between the distributions of the boys and the girls. The distributions 
for the boys at each age between 6 and 13 years show a greater distance, 
measured in kilogram-centimeters, from the median to the 80-percentile 
than from the median to the 20-percentile, in 5 ages out of 8. The 
total difference is also slightly greater between the median and the upper 
80-percentile. On the other hand, the table for the girls at these ages 
shows the 20-percentile farther from the median in 5 out of 8 ages, with 
a total difference considerably greater than that shown for the boys. 
Usually the differences were small compared with their errors. With 
the boys only at age 13 was the difference in favor of the 80-percentile 
three times its probable error, while with the girls the four oldest ages 
show the distance of the 20-percentile greater by three times its prob- 
able error. 

A comparison with the reports of Smedley on this test for the previous 
year (Report No. 2), leaves his results still more uncertain. While 
he does not give the medians at each age, we may make less satisfactory 
comparisons between the distance of the 10-percentile from the 25- 
percentile and the distance of the 90-percentile from the 75-percentile. 
If we do this, we find the distance is uniformly greater at the upper 
end of the distributions for each age both for the boys and girls. The 
Smedley results are, therefore, decidedly contradictory. The first 



272 DEFICIENCY AND DELINQUENCY 

year shows distributions skewed toward excellence and total results for 
two years show distributions skewed mainly toward deficiency. 

Broadly considered, the Binet records with school chil- 
dren point to a skewed distribution toward deficiency 
when large allowance is made for the difference in value 
of the year units. It is extremely rare to find a child 
testing 4 years in advance of his life-age, while 15-year- 
old idiots are presumed to test 12 year-units or more under 
a mature standard. 

Pearson believes that "the Gaussian curve will be found 
to describe effectively the distribution of mental excess 
and defect' ' for intermediate ages as measured by Jaeder- 
holm's form of the Binet scale. The data on which Pear- 
son places reliance are Jaederholm's results in testing 261 
normal children 6-14 years of age in the Stockholm schools 
and 301 backward children in the special help classes of 
the same city. The best fit of a normal curve to the data 
was obtained with a group of 100 8-year-old children, in 
which case the chances were even that samples from a 
normal distribution would fit. With his larger normal 
and backward groups combined in proper proportions in 
one population the chances were 20 to 1 that such a dis- 
tribution as was actually found would not fit into the 
Gaussian distribution. He admits that "this is not a 
very good result," although it is better than when the 
Gaussian curve is fitted to either the normal or the back- 
ward group alone. In a subsequent paper he gives each 
child a score relative to the standard deviation of the nor- 
mal child of his own age, a method comparable to his treat- 
ment of Norsworthy's data. He then finds that "10% 
to 20% or those from 4 to 4.5 years and beyond of mental 
defect could not be matched at all from 27,000 children" 
{164, p. 46). In each case the distributions actually found 
were skewed somewhat toward deficiency. Furthermore, 



MEASUREMENT OF MENTAL DEVELOPMENT 273 

when he suggests that —4 S. D. may be used as a borderline 
for tested deficiency, he recognized that the mental ability 
of children is skewed so far as the empirical data are con- 
cerned. With a normal distribution there would not be 
two children in 100,000 who would fall below this border- 
line. Nevertheless, the normal curve serves for most 
practical purposes to describe the middle ranges of ability. 

Pearson thinks that the skewed distributions of his 
data may possibly be explained by the drawing off of older 
children of better ability to the "Vorgymnasium,'' or to 
the higher-grade schools, by the incompleteness of the 
higher age testing, or by the "possibility of the existence 
of a really anomalous group of mental defectives, who, 
while continuously graded inter se, and continuously grad- 
ed with the normal population as far as intelligence tests 
indicate, are really heterogeneous in origin, and differ- 
entiated from the remainder of the mentally defective 
population' ' (164, p. 34). The last hypothesis, of course, 
supposes that mental ability is skewed and suggests the 
cause. He supplements this explanation by stating that 
the heterogeneous cause of the "social inefficiency ,, of 
the deficients may not be connected directly with the 
intellect but affect rather the conative side of the mind. 
A skewed distribution under biological principles of in- 
terpretation supposes a single cause or group of causes 
especially affecting a portion of the population. 

It is also to be noted that the apparent form of distri- 
bution may be the result of the nature of the test and the 
units in which it is scored. Some tests might not dis- 
criminate equally well a difference in ability at the lower 
and at the upper ranges of ability. If the test were too 
easy the group might bunch at the upper portion of the 
scale and the distribution appear to be skewed toward 
the lower extreme where there were only a few cases. 



274 DEFICIENCY AND DELINQUENCY 

If too difficult a test were used the form of distribution 
might shift in the opposite direction,, most of the group 
ranking low. It is extremely difficult to formulate mental 
tests so that they will equally well measure differences at 
each degree of ability. This objection should not hold, 
however, if the scoring were in units of time for the same 
task, as with the form board test. The essential character- 
istics of a test in order that it may indicate the form of a 
distribution is that the units of scoring shall be objectively 
equal under some reasonable interpretation and that they 
shall be fine enough to discriminate ability at each position 
on the scale. Under such conditions the variations in the 
difficulty of tests should not obscure the form of the dis- 
tribution of the ability tested. 

Turning to the analogy of measurements of physical 
growth, a strong argument may be made for the hypothesis 
of shifting forms of distribution. As Boas points out re- 
garding measurements of the body at adolescence, owing 
to the rapid increase of the rate of growth the distribu- 
tion of the amounts of growth is asymmetrical "the asym- 
metry of annual growth makes also all series of measure- 
ments of statures, weights, etc., asymmetrical." More- 
over, "acceleration and retardation of growth affects all 
the parts of the body at the same time, although not all 
to the same extent . . . Rapid physical and rapid 
mental growth go hand in hand" {80). There is no reason 
to suppose that the brain is free from this phenomenon 
of asymmetrical distribution of annual increments of growth 
among children of the same age when the rate of 
growth is changing as at adolescence. It is therefore to 
be expected that the separate age distributions would be 
skewed at early ages and at adolescence even if the dis- 
tribution should be normal with a static population. The 
presumption from physical measurements is that the form 
of distribution shifts with age. 



MEASUREMENT OF MENTAL DEVELOPMENT 275 

Again we may note that if some of the idiots reach an 
arrest of development before any of the normal individuals, 
as several investigators contend, this would imply that 
the distributions must be skewed unless there is a curious 
corresponding acceleration of growth on the part of gen- 
iuses to balance this lagging by idiots. 

In spite of these arguments and the evidence of asym- 
metry of measurements at least at some periods of life 
it is to be noted that current opinion is probably contrary 
to this hyposthsis, although, as I believe, because it has 
been concerned mainly with those who are not of extreme 
ability. For all large medium ranges of ability slight 
skewness might well be negligible. It is interesting to 
note that Galton says that "eminently gifted men are 
raised as much above mediocrity as idiots are depressed 
below it" (159, p. 19). Measured by intelligence quo- 
tients with the Stanford scale, Terman finds among school 
children that deviations below normal are not more com- 
mon than those above (197, p. 555). Burt, following a 
suggestion of Cattell as to college men, however, seems to 
incline to the opinion that the general distribution of 
ability, like wages, is skewed toward the upper end. He 
adds, "In crude language, dullards outnumber geniuses, 
just as paupers outnumber millionaires" (85). 

(d) EQUIVALENT UNITS OF DEVELOPMENT WHEN THE 
FORM OF DISTRIBUTION IS UNCERTAIN. 

For our problem of units and scales of measurement, an 
asymmetrical distribution sets a very difficult problem. 
It may be that this very difficulty has been one of the 
main reasons for slowness in recognizing the drift of the 
evidence. In order to set forth the difference in the con- 
ception of measurement when distributions become asym- 
metrical I have presented this hypothesis in connection 



276 DEFICIENCY AND DELINQUENCY 

with the curves of development in Fig. 5. It will be noted 
that if the distributions of mental capacity vary in sym- 
metry, the units of standard deviation change in signifi- 
cance from one form of distribution to another. Minus 
2 S. D. may exclude very different portions of groups dif- 
ferently distributed, while it would always exclude the 
same proportion if the distributions had the same sym- 
metry, or skewness. 

Under conditions of variable symmetry there is a 
sense in which the same relative physical score in units 
running from zero ability to the best ability would always 
have an equivalent objective meaning, but this might not 
express equivalent development conditions at different 
ages. For example, with shifting forms of distribution, 
to say that a child of six years had reached three-fifths of 
the best development for his age on an objective scale 
might give no significant indication of how nearly he was 
keeping pace with those three-fifths of the best ability 
of another age. Neither would his position in units of 
the deviation of ability at his age give this information 
without knowledge of the form of the distribution of 
ability at his age. With varying forms of distribution 
at different stages of development this would afford an 
insurmountable difficulty. 

With unknown or varying types of distribution it is de- 
sirable to utilize percentiles as equivalent units for com- 
paring individuals at different stages of development. 
They differ somewhat from ranks in an order of notice- 
able differences. With an indefinitely large group, such 
ranks would mark off only those cases which were in- 
distinguishable in merit. These units would be num- 
bered in order from the highest to the lowest in ranks of 
just distinguisable merit, a different number of individuals 
conceivably occuring at the single steps. -Psychologic- 



MEASUREMENT OF MENTAL DEVELOPMENT 



277 



Objective Units 



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278 DEFICIENCY AND DELINQUENCY 

ally the percentiles are somewhat less significant because 
they are not conceivable in steps of just noticeable dif- 
ferences. Percentiles have less value in comparing 
abilities in the same distribution, but have decided ad- 
vantages when comparing corresponding abilities in diff- 
erent distributions. Except at points where merit is in- 
distinguishable, they signify that a certain proportion of 
a group is ahead in the struggle for existence. They are 
thus units of relative rank. Moreover, they are directly 
translatable into units of the deviation in case the form 
of the distribution of ability has been determined. This 
is a special advantage if the forms of distribution turn out 
to be normal or even uniform. 

In using percentiles it is to be remembered that equal 
differences between percentiles are not comparable in the 
same distribution except in the sense of the same extra 
proportions of the group to be met in competition. A 
change in the degree of ability from the lowest percentile 
to the lowest 2 percentile would be very different from the 
change in the degree represented by the 50 percentile to 
the next precentile above. Differences in the ability 
of individuals ranking near each other in the middle of 
the same percentile series would be distinguished with 
difficulty while it would be easy to make such discrimin- 
ations at the extremes. 

The special value of the percentile units in measure- 
ment of ability lies in the comparison of individuals of 
corresponding position in corresponding groups in which 
the ability may not be assumed to distribute alike. The 
concept that 995 out of every 1000 randomly selected in- 
dividuals at his age are ahead of a particular individual 
in the struggle for existence has very definite and signi- 
ficant meaning which is quite comparable from one period 
of life to another regardless of the form of the distribution. 



MEASUREMENT OF MENTAL DEVELOPMENT 279 

We shall return to this question of equivalent units in 
distributions of unlike symmetry when we compare the 
definitions of the borderlines of deficiency in terms of in- 
telligence quotient, coefficient of intelligence, standard 
deviation and percentage. Corresponding percentages of 
corresponding groups have a more useful definite signifi- 
cance of equivalence than any other units of measurement 
of mental ability available when the forms of distribution 
vary at different stages of development or are uncertain, 
as seems to be true with tested abilities. 

B. The Curves of Mental Development. 

When we endeavor to make our ideas of mental devel- 
opment more definite, we are assisted by thinking of the 
various stages in graphic form. This is especially true 
when trying to think of the position of the deficient in- 
dividuals, relative to the average individuals and to genius. 

In diagrammatically presenting these concepts in Fig. 3 
and Fig. 5 we do not wish to assume that all the principles 
on which the developmental curves have been plotted 
have been decided. If they make clearer the points still 
under discussion and direct the discussion to specific 
features so that more data may be brought to bear upon 
the empirical determination of their characteristics, they 
will serve a useful purpose. For our present ends, we 
shall consider only certain features which have a bearing 
upon the interpretation of developmental scales and the 
quantitative definition of the borderline. 

In the graphic presentation of the curves of develop- 
ment in Figures 3 and 5 the relative position at various 
ages has been suggested hypothetically for those of the 
best ability and median, or middle ability, as well as the 
borderline of the deficients. 



280 DEFICIENCY AND DELINQUENCY 

It is evident that these graphs should represent equival- 
ent ability at each stage of development measured by 
as objective a scale of measurement as possible. In the 
graphs this scale is assumed to be composed of physical 
units with its zero at zero ability. The deficient group 
is distinguished by the portion with a grated shading. 
The distribution curves of individual ability we have al- 
ready mentioned in connection with scales of measure- 
ment. Fig. 3 is constructed on the assumption of a nor- 
mal distribution of ability at each age extending to the 
same zero ability. Fig. 5 on the assumption of distribu- 
tions of varying form. 

Otis has given a very able logical analysis of certain 
concepts underlying the testing of mental development 
(163). His discussion differs from the present in its aim 
to determine the proper mental age for particular tests, a 
question which I have not considered. It also supple- 
ments the present discussion by showing the changing 
value of the same intelligence quotient with normal dis- 
tributions of ability under certain assumptions as to 
range of ability and decrease in the annual increments of 
ability with age. 

(a) THE SIGNIFICANCE OF AVERAGE CURVES OF DEVEL- 
OPMENT. 

Some investigators are apparently inclined to question 
the significance of any curve of mental development on 
account of the very different forms of development which 
they have found in particular cases. A quotation from 
Goddard will state this problem: 

"It seems to me that there is considerable evidence 
that there are a good many children that develop at a 
normal rate up to a certain age and then slow down; 



MEASUREMENT OF MENTAL DEVELOPMENT 281 

some slowing down gradually and others rapidly. This 
is possibly accounted for by accidental conditions. Dr. 
Healy's case of traumatic feeble-mindedness is a good 
illustration of this. We have quite a good many cases, 
not a large percentage as yet, where it is pretty clear 
that they have developed very nearly normally up to the 
age of seven, eight or nine, so that I am very skeptical 
as to the possibility of formulating a rule for determining 
the rate of development. Many cases are uniform in 
slowness while others vary a great deal; some slow up 
more rapidly than others as has already been stated . . 
"Morons are not usually discovered until twelve or 
fourteen years of age. The picture to me of the develop- 
ment of the feeble-minded is rather that these different 
types develop each in his own way very much as the 
physical side develops. Different families have different 
determiners of development. Just as it was determined 
before I was born that I should be five feet, ten inches 
tall, I developed that height and no further. In the 
same way, probably, that determiner carries with it the 
determination of the rate of development and the time. 
This carries with it the fact that I should have been an 
average boy from birth. As a matter of fact I was very 
much under-size until I was fifteen or sixteen years of 
age. Then I shot up. Other cases are over-size. It 
may be a false analogy, but it seems to me to illustrate 
the rate at which these cases develop" (111). 

This view raises clearly the question how far the curve 
of average development represents a common tendency 
of different individuals in development. Are the indi- 
vidual curves of development so varied in form that an 
average curve does nothing but obscure their significance? 
The study of individual curves of growth in height and 
weight by Baldwin indicates that the bigger children tend 
to develop earlier, the smaller later (73). The individual 
curves of mental development may be analogous. If so, 
the average curves may not adequately represent the 
common tendencies of development. Nevertheless, it 
is to be remembered that with height and weight the av- 



282 DEFICIENCY AND DELINQUENCY 

erage curves do retain a decided usefulness, which no- 
body, I suppose, would seriously question. 

An analogous problem arises when we consider the 
question of variations in the maturity of different mental 
processes. Besides the question whether the average 
curve is useful in view of the variation among individuals 
in their rates of maturity for the same process, the psy- 
chologists have a still more difficult problem about curves 
of general ability. These curves are built by combining 
the results of numerous psycho-physical tests which are 
very different in type. We need to raise the question 
whether the type of process measured by memory for 
digits, for example, matures at the same rate as those 
processes measured by other memory tests: in general, 
how much a single test or combination of tests represents 
a common process. Furthermore, we need to inquire 
whether processes measured by memory tests mature like 
those measured by tests emphasizing reasoning, imagina- 
tion, motor ability and other groups of activities. We 
thus have the problems of the different rates of maturity 
of the different tested processes in the same individual 
and of common tendencies among these specific processes. 

In order more clearly to present this problem of the 
significance of developmental curves for different processes, 
I have brought together the age norms from 8 to 14 years 
for 40 tests as given by different investigators. No norms 
were included which were not based on tests of at least 
25 individuals. After 14 years the data which have been 
collected are open to the objection that the norms for the 
older ages would be seriously affected by the fact that they 
were obtained upon children remaining in school, usually 
in the elementary school, i. e., upon groups, among which 
a large portion of those of better or of poorer ability had 
been eliminated. The relative position of the norms for 



MEASUREMENT OF MENTAL DEVELOPMENT 283 

older ages are, therefore, not comparable with those of 
children who are of the ages of compulsory attendance. 
The results published are inadequate below 8 years for 
most of the tests, so I have not extended the curves to 
earlier ages. In 14 instances the data for boys and girls 
were only given separately. In these I have used the 
norms for the boys. A pre-pubertal break in a combined 
curve may, therefore, indicate a sex difference. In most 
cases the norms were given for the sexes combined, and 
the difference is unimportant for the points considered. 
The variation in age norms with different tests is shown 
graphically in Figures 6, 7 and 8. In order that the 
various tests may be plotted on the same scale, so as to 
compare changes in development for the different tested 
processes, I have used the average increase in ability 
from 8 to 9 years of age for each test as a common measure 
and arbitrarily plotted the slant of the curve between 
these ages at 45 degrees. The increase from 8 to 9 is re- 
presented by 10 units on the objective scale to the left 
of the graphs. On this basis it is possible roughly to com- 
pare changes in the absolute annual increase at different 
ages for the same test and for different tests. It assumes 
that the units in which each test is scored are equivalent 
for that test. An average difference between the basal 
ages or between any two ages cannot be assumed to be 
accompanied by the same distribution of increases. More- 
over, the 8-year norm is at different distances from zero 
for the different tests so that the relative increase from 8 
to 9 cannot be regarded alike for the different tests. The 
method, however, is sufficiently accurate for illustrating 
the very different forms of the developmental curves 
which might be expected if they were measured by absolute 
increases from year to year. Even the variation in the 
slant of the lines at the different ages gives a graphic pic- 



284 DEFICIENCY AND DELINQUENCY 

ture which will assist in interpreting the significance of 
average curves of general ability. As the curves stand, 
they show the norms for each age for any test, as if placed 
on its own objective scale, and the various objective 
scales have been harmonized on the assumption that the 
norms at 8 and 9 years are accurate. We thus have a 
simple representation of the absolute changes in the abil- 
ities tested from age to age by the same tests relative to 
a single objective scale. It will not give a seriously er- 
roneous picture for any tested ability so long as the units 
in which the particular test is scored may be presumed 
to be objectively equal. 

The tests on which Figures 6, 7, and 8 were based included practically 
all which were reported in the researches used. They were as follows: 
Norsworthy (159), perception of 100-gram weight, cancelling A's 
(boys), ideas remembered from four simple sentences, memory of re- 
lated and of unrelated words, part-wholes, genus-species, opposites 
and reverse of opposites given the next day, "a-t" test. J. Allen Gil- 
bert (108) f taps in 5 seconds, fatigue in tapping, visual reaction time, 
color-discrimination reaction time, reproduction of 2- second interval. 
Smedley (51, No. 3), strength of right-hand grip (boys), taps in 30 
seconds (boys), ergograph; visual, auditory, audio- visual, and audio- 
visual-articulatory memory for digits. W. H. Pyle, Standards of 
Mental Efficiency (J. of Educ. Psychol, 1913, IV., 61-70), uncontrolled 
association, opposites, part-wholes, genus-species, digit-symbol and 
symbol-digit substitution, memory for concrete and for abstract words, 
memory of Marble Statue selection, (only boys' norms used for each). 
Pyle and Anderson combined by Whipple (220) two word-building 
tests (boys). Anderson as given by Whipple memory for letter squares. 
D. F. Carpenter, Mental Age Tests (J. of Educ. Psychol., 1913, IV., 
538-544), substitution of colors in forms and of numbers in forms, 
perception time in marking A's, concentration, i. e., difference in time 
of last test under distraction, memory of pictures of objects, all tests 
devised by Carrie R. Squire. Stenquist (54), construction test. Syl- 
vester (191), form-board test. 

In Fig. 6 curves A and B are Smedley 's tests; curve C includes in 
addition Norsworthy's unrelated words, Pyle's memory for concrete 
and abstract terms, Anderson's letter-squares, Carpenter's memory for 



MEASUREMENT OF MENTAL DEVELOPMENT 285 



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Fig. 6. Tests of the Development of Memory Processes. Medians at 
Each Age of the Central Tendencies of the Tests. 



286 DEFICIENCY AND DELINQUENCY 

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Fig. 7. Different Types of Development. Medians at Each Age of the 
Central Tendencies of the Tests. 



MEASUREMENT OF MENTAL DEVELOPMENT 287 



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Fig. 8. Forty Curves of Development. Distribution \at Each Age of the 
Central Tendencies of the Tests. 



288 DEFICIENCY AND DELINQUENCY 

pictures, and Gilbert's for the time interval; curve E includes Pyle's 
two and Carpenter's two substitution tests; curve F includes Pyle's 
Marble Statue and Norsworthy's memory for related words and for 
sentences; curve S is North worthy's ; curve D is the combination of 
these 17 tests. 

In Fig. 7 curve H includes Gilbert s visual reaction time, Norsworthy's 
A and a-t tests, Carpenter's two A tests; curve I includes Gilbert's 
and Smedley's tapping tests; curve J is the median of the central 
tendencies of all 40 tests; curve K includes Norsworthy's two opposites 
and her part- whole and genus-species tests, the Pyle opposites, genus- 
species and part- whole tests; curve L is the same as D, curve M includes 
Smedley's strength of grip and ergograph tests and Gilbert's fatigue of 
tapping; curve N includes Pyle and Anderson's word building tests 
and Pyle's uncontrolled word association test. 

In Fig. 8 curve P is Gilbert's visual reaction time test, curve S is 
Norsworthy's test for memory of unrelated words, the other curves 
are the median and quartiles for the central tendencies of all 40 tests 
after each was expressed at each age in terms of the gain from 8 to 9 
years taken as a unit. 

Several points are to be noted about the nature of the 
curves for different tests. In Fig. 6 showing the curves 
for different forms of memory tests, that for the memory 
of digits is very different in character from that for memory 
of related material. The most extreme differences in the 
time of maturity are shown by the test for memory for 
digits presented orally and the substitution of color in 
forms, the former continues to increase so rapidly relative 
to the absolute increase from 8 to 9 years that it cannot 
be represented in the graph reaching 539 units of the scale 
by 14 years of age, while improvement in ability in the 
latter is not measured after 9 years. We cannot take 
time to discuss how much of the differences between the 
various curves may be due to the nature of the tests 
themselves, the form of scoring the results, or the condition 
under which they were given, selection of subjects, etc. 
The conclusion is safe, however, that when groups of 
three or four tests of similar type show such marked differ- 



MEASUREMENT OF MENTAL DEVELOPMENT 289 

ences as those for memory of digits and memory for re- 
lated material we may expect similar differences in the 
rates of maturity of the corresponding processes. 

From Fig. 7 we may learn that tests emphasizing func- 
tions such as speed of motor or perceptual motor reaction, 
curves H and I, are notably different in their form from 
curves for tests of imaginative processes, curve N. As 
we group tests together covering larger ranges of activity 
we approach the median curve for general ability. Note 
the median curve for 17 memory tests (curve L) compared 
with the median for the 40 tests (curve J). By empir- 
ical studies we might pick out types of tests which would 
most closely represent the maturity of average ability. 
For example, the median for the substitution tests, curve 
E, resembles the median for the memory tests, curve D, 
more closely than does that of the 4 digit tests, curve B. 
Curve K, for 7 association tests, resembles the median 
for the 40 tests, curve J, much more closely than the curve 
for the perceptual-motor speed tests, curve H. This 
difference can not be explained by the use of 7 instead of 
5 tests in calculating the central tendency of the group. 
It probably means that the sort of psycho-physical pro- 
cesses usually tested more closely represent on the aver- 
age the abilities shown in association tests than they do the 
abilities shown by speed of motor reaction. The signi- 
ficance of this sort of analysis for those constructing a 
scale for measuring intellectual ability is obvious. 

Fig. 8 shows the median and quartile range for the 
central tendencies of the 40 tests and gives examples of 
two extremely different tests, visual reaction time and 
memory for unrelated words. How closely these particular 
tests represent fundamental differences in the maturity of 
different processes, we cannot, of course, be sure without 
prolonged research; but nobody would question that 



290 DEFICIENCY AND DELINQUENCY 

analogous differences would be found in different processes. 
When we think of curves of general ability we must, there- 
fore, keep in mind the light which might be thrown on 
them by an analysis of the various processes tested in the 
particular scale used. 

Another feature of all developmental curves which is 
apparent as soon as the causes of development are con- 
sidered, is that growth in an individual is the result of 
several factors. These include the native capacity, the 
rate at which that capacity manifests itself instinctively, 
and the external stimuli which encourage or retard that 
manifestation. To some extent these factors van' inde- 
pendently. Our curves of development will never com- 
pletely express all the facts until they analyse out all these 
factors for each of the processes. In the meantime we 
shall be able to think of general trends of development by 
considering average curves. The fact that they represent 
combinations of unanalyzed factors must, however, make 
us very cautious in interpreting our norms. 

b - CHANGES IN THE RATE OF DEVELOPMENT. 

There has been considerable discussion of the form of 
the curves of mental development. The logical aspects of 
the curves on the assumption of normal distribution of 
ability at each age and uniform age of maturity have been 
treated by Otis 163 ; and the bearing of these assumptions 
upon the Binet scale pointed out. Thorndike has plotted 
the developmental curves for a dozen tests on the basis 
of the variability at 12 years of age used as unit and gives 
a chapter in his Educational Psychology to the changes 
with maturity (198, Chap. XI). Bobertag suggests that 
the rates of development of normal and deficient children 
are analagous to the upward progress of two projectiles 
fired from such different heights that the force of gravity 



MEASUREMENT OF MENTAL DEVELOPMENT 291 

would retard the lower projectile more than the upper (Si). 
This analogy supposes that the rate of maturity would 
continually decrease and that those who were feebler 
mentally would be arrested in their developmental earlier. 
Bobertag, Kuhlmann {137, 138) and Otis give evidence 
from the results of Binet testing that the rate of develop- 
ment decreases with age. The percentages of older chil- 
dren passing certain positions on the Binet scale or certain 
tests taken from it were found to change less at year in- 
tervals for the older ages. This evidence is not conclusive 
unless we know that the positions compared are at the 
same point in the distributions of ability at the beginning 
of the periods of growth. The same percentage change at 
a point farther away from the central tendency would 
mean a larger growth than at the middle of the distribu- 
tion, when judged either in reference to a physical scale 
or to units of deviation. 

While recognizing that the complete curve of mental 
development is logarithmic in form Pearson contends 
that, when measured by Jaederholm's adaptation of the 
Binet scale, development is adequately represented by a 
straight line from 6 to 15 years of age (164). As this con- 
clusion is based upon the use, as equivalent units, of 
years of excess and deficiency at all these ages the data 
lacks the cogency of a scale of equal physical units. 

With the Point Scale it is not known whether the units 
in different parts of the scale are equivalent. Without 
assuming that they are equal it is impossible to discover 
the form of curves of development from the records of 
children at a series of ages. Yerkes and Wood publish 
a curve of the increase of intellectual ability based upon 
point-scale measurements, which resembles in form the 
hypothetical curves. They say: 



292 DEFICIENCY AND DELINQUENCY 

"The point-scale method has the merit of indicating 
directly the rate, or annual increments of intellectual 
growth. We do not claim for our measurements a high 
degree of accuracy, especially in the case of the early 
years of childhood. But even the roughly determined 
curve of intellectual growth from four to eighteen years, 
which we present below, has considerable interest for the 
genetic psychologist and for the psychological examiner. 
We have ascertained that whether measured by the ratio 
of the increment of increase, year by year, to the norm for 
the appropriate year or by the ratio of the extreme range 
of scores to appropriate year norms, intellectual develop- 
ment rapidly diminishes in rate, at least from the fifth year 
onward" (169, p. 603). 

Waiving the question whether annual increases or the 
range of measurements relative to the age norms would 
be satisfactory indications of the change in the rate of 
growth, it seems to be fairly clear that neither of these 
criteria would be adequate unless we first knew that the 
units in which they were measured were equivalent at 
different portions of the scale. To show that the point 
scale units are even theoretically equivalent it would seem 
to be necessary to assume, on the basis of normal distri- 
bution of ability, that each unit of the deviation for each 
age distribution either equaled the same number of scale 
units or the same proportion of the total distance from 
lowest to highest ability at each age measured in the point- 
scale units. The originators of the scale do not seem to 
have planned it with this in view. Moreover, the diffi- 
culty of empirically demonstrating such equivalence of 
units on a point scale or any form of the Binet scale pre- 
vents its use for indicating curves of mental development, 
however serviceable it may be for other purposes. 

The simplest demonstration of the form of the develop- 
ment curves is applying the same test, scored in equal 
physical units, to children of different ages. In Figs. 6, 



MEASUREMENT OF MENTAL DEVELOPMENT 293 

7, and 8 the evidence from tests was assembled for ages 
8 to 14 inclusive. It is probable, however, that the form 
of these development curves, when the unit of measure- 
ment was anything but time taken for the same task, has 
been affected by the difference in the real value of units 
called by the same name, e. g., giving the opposite of one 
word is not always equal to giving the opposite of another. 

The best developmental curves empirically determined 
are probably those for the form board presented by Syl- 
vester {191), Wallin (212) and Young (227) since in each 
of these cases the same test was presented at all ages and 
the scores were in equal physical units of seconds. It 
can hardly be supposed, however, that the form board 
curves alone would be typical of average mental develop- 
ment. To know something about the general curve of 
mental development we need a combination of a number 
of mental tests scored on scales of equal units. These 
may be either equal physical units or units on scales for 
mental development similar to those of Thorndike and 
others for measuring educational products, handwriting, 
arithmetic, spelling, etc. 

That either a straight line or a simple curve would re- 
present the development of ability from birth to maturity 
is very doubtful. . When we consider the entire develop- 
mental curve from birth nobody doubts that there is a 
change in the rate of development at the time of the arrest 
of instinctive changes at adolescence. There are prob- 
ably fluctuations in the rate before this final arrest. Pint- 
ner and Paterson also assume a complex curve of develop- 
ment (44). Whether the fluctuations should be allowed 
for in the description of the borderline of deficiency is the 
important question in our study. With measurements of 
bodily growth we noted that changes in the rate of matur- 
ity are accompanied by a skewness of distribution of 



294 DEFICIENCY AND DELINQUENCY 

ability at the ages affected. The same effect may be 
expected with mental measurements. The percentage 
method of defining the borderline of deficiency has an 
advantage when the form of distribution at any age is 
uncertain (See Chap. XIV, d.). Since the changes in the 
rate of development are most likely to be important at the 
prepubertal and adolescent ages the description of the 
borderline in terms of deviation or quotient may be ex- 
pected to be most uncertain at this period. Moreover, 
none of the quantitative definitions of the borderline, 
except the percentage method, remain equivalent if rates 
of development of normal and deficient children change 
relative to each other, a question we shall now consider. 

(C) THE QUESTION OF EARLIER ARREST OF DEFICIENT 
CHILDREN. 

It has been assumed by Bobertag (Si), Stern (88), 
Goddard (117) and others that deficient children reach 
their maturity earlier than normal children. If this were 
true the curves of mental development for the average 
and for the deficient children should not be expected to 
retain their same relative positions after the idiots had 
begun to show arrested development. Moreover, unless 
this arrest were compensated by some peculiar form of 
accelerated growth among those above normal ability, we 
might expect that the distributions of ability would 
change in form at the various ages after arrest had begun. 
A relative increase in the distance of older deficients from 
the average as compared with younger deficients may be 
interpreted as meaning either the earlier cessation of 
growth of the deficients or a change in the relative rates 
of growth of individuals of different mental capacity. 
When fully considered the present evidence from the Binet 
tests fails, I believe, to demonstrate the earlier arrest of 



MEASUREMENT OF MENTAL DEVELOPMENT 295 

the deficients, although it is undoubtedly true that the 
Binet scale may not be fine enough to measure the improve- 
ment of idiots. We shall take up certain investigations 
that bear upon this point. 

Goddard has reported tests upon the same group of 
346 inmates in an institution for the feeble-minded who 
were tested three years in succession (117). The paper 
suggests that the idiots, as a group increased less in ab- 
solute ability than those of higher mental age. The 
average gain for 55 idiots who tested I or II mentally was 
about half a test in the two years. In order to reach our 
present problem, however, we must know that the idiots, 
for example, developed relatively less mentally than did 
those of the higher grades of ability in the imbecile and 
moron groups of the same life-ages. This question can- 
not be answered from the paper. It probably cannot be 
adequately answered from mental age results on account 
of the irregularity in the value of the year units at different 
points on the Binet scales. 

Bobertag summarizes Chotzen's data obtained by the 
examination of the children in the Breslau Hilfsschulen 
with the Binet scale. He believes that the position on 
an objective scale attained by the average of these re- 
tarded children is progressively lower with advancing 
age relative to the average position attained by normal 
children, assuming that the quotient for normal children 
remained constant at each age. The average intelligence 
quotients of all the children in the special schools (exclus- 
ive of those testing III or less) was 0.79 for those 8 years 
of age, 0.72 for those 9 years, 0.70 at 10, and 0.67 at 11- 
12 (Si, p. 534). 

Stern also compiled a table from Chotzen's results 
which shows this decrease in intelligence quotients with 
life-age separately for each group of those whom Chotzen 



296 



DEFICIENCY AND DELINQUENCY 



by his expert diagnosis regarded as imbeciles, morons, doubt- 
ful, and not feeble-minded although attending the special 
schools (188, p. 80). This table is reproduced here as 
Table XX. On the surface it suggests that the quotients 
of the extreme groups are nearer together at the older 
ages, instead of being farther apart. The objection to 
this evidence from the Binet scale is that the norms are 
not equivalent for different ages on the scale used. Since 
the objective norms on the Binet scale are more difficult 
to attain at the older ages this variation would tend to 
make older children show lower quotients than the same 
children would show at younger ages, so that such tables 
are quite uncertain in significance. 

TABLE XX 

Average Intelligence Quotients of Children of Different 
Ability. (From Chotzen's Tables X & XI.) 



Life 
Age 


Not Feeble- 
minded 


Doubtful 

Defect 


Morons 


Imbeciles 


8 


0.92 


0.84 


76 


0.71 


9 


0.85 


0.81 


0.77 


0.67 


10 


(0.80) 


(0.80; 


0.74 


0.62 


11 


(0.73) 


(0.68) 


0.71 


(0.64) 


12 


(0.75) 


(0.75) 


(0.73) 


(0.61) 


13 




(0.73) 







The Jaederholm data with his form of the Binet scale, 
as treated by Pearson, shows a straight regression line 
for the backward children which falls below the normal 
development line on the average four months of mental 
age for each additional year of life from 7-14 (167) . Accept- 
ing Pearson's interpretation that a year of excess or defici- 
ency and a year of growth is a constant unit, we find that the 
deficient group from special classes was falling contin- 
ually behind the normals with increase of age a relatively 
greater distance from any rational reference point. Pear- 
son accounts for this change in the distance between the 



MEASUREMENT OF MENTAL DEVELOPMENT 297 

two groups of normal and backward children, as I under- 
stand his paper, by supposing that with increase in age 
more and more normal children become deficient. It 
would seem that this data would be more easily explained 
by supposing that the distributions became skewed to- 
ward deficiency for the older ages, rather than that the 
distributions remained normal and became flatter. 

The best evidence as to the relative positions of the 
curves for deficients and those for average ability would 
be provided by using psychological tests that could be 
adequately scored in terms of equal physical units for the 
same task. The position of various lower percentiles 
relative to the average or to an assumed reference point 
could then be compared on the same objective scale. I 
have reviewed studies of this type in discussing skewed 
distributions in Chap. XIII, A, c. I there reached the 
conclusion that the weight of the evidence was that the 
distributions were slightly skewed in the direction of 
deficiency, although the evidence was not conclusive. 
We are now raising the further question whether this 
skewness increases with age. 

On account of the difficulty of determining the points 
for zero ability in terms of the physical scales used, let us 
see what conclusion might be reached if we calculated the 
relative distance of median and low ability of equivalent 
degree from the scores of the same higher degree of ability 
assumed as a reference point at the various ages. There 
seems to be no reason in the theory of measurement why 
the highest score instead of the lowest score in random 
samples might not be used for a reference point for compar- 
ing the distances between normal and deficient children 
at different ages. Instead of using the highest single score, 
it would be better to use the upper quartile or quintile 
since it would be less affected by a chance error in giving 
the test. 



298 DEFICIENCY AND DELINQUENCY 

Applying this method to determining the relative posi- 
tion of median and retarded ability I have calculated the 
data for the form board test cited previously from Syl- 
vester (191) and from Young (227). This affords the only 
adequate evidence of which I know, derived from tests 
scored in equal physical units given to sufficiently large 
groups to indicate whether or not the retarded group 
changes its relative position from the normal group at 
different ages. The comparison is shown in Fig. 9. With 
Sylvester's data the distance of the lower quartile in 
ability from the median is compared with the distance of 
the upper quartile from the median, the latter distance 
being taken as a unit. With Young's data for Witmer's 
form board the quintile is used instead of the quartile and 
each sex is given separately. Since Young's table shows 
the scores for half ages, it was necessary to take the aver- 
age of the two scores, thus giving the approximate score 
for the middle of the complete age group. The graph dis- 
closes no pronounced tendency for the retarded group to 
fall relatively farther behind the median with increase in 
age. There are, however, notable fluctuations in the rela- 
tive positions of the groups so that at 7 years with Young 's 
data for boys and at 13 years for Sylvester's curve the 
retarded group is twice as far from the median relative to 
the distance between the median and the corresponding 
better group as it is at some other times. It is possible 
that the curves for the older groups of those of poorer 
ability are too high since it is likely that more of the actu- 
ally deficient children tend to be dropped from the public 
school classes with increase in age. Nevertheless, so far 
as the evidence at present goes it is not sufficient to deter- 
mine whether the backward and the corresponding better 
group show a general change in their relative distances 
from the median with approach to maturity. 



MEASUREMENT OF MENTAL DEVELOPMENT 



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300 DEFICIENCY AND DELINQUENCY 

On the other hand the curves indicate the tendency for 
the distributions to be skewed toward deficiency and for 
the relative distances to fluctuate as we should expect if 
the accelerations in growth occured at different ages for 
those of different ability. The data of Young suggest 
that there may be sex differences in the age of accelera- 
tion, the backward girls showing accelerations, relative to 
the upper group at ages 7 and 12, a year or more before 
the boys. For Sylvester's data the ratio of the distance 
between the median and the lower quartile divided by the 
distance between the median and the upper quartile for 
each of the age groups is as follows: 5 yrs. 1.8, 6 yrs. 

2.4, 7 yrs. 3.0, 8 yrs. 2.0, 9 yrs. 2.2, 10 yrs. 2.4, 11 yrs. 
2.0, 12 yrs. 1.8, 13 yrs. 3.0, 14 yrs. 2.1. For Young's data 
the corresponding ratios are — Boys: 6 yrs. 1.5, 7 yrs. 1.9, 
8 yrs. 1.5, 9 yrs. 0.8, 10 yrs. 1.6, 11 yrs. 1.2, 12 yrs. 1.4, 
13 yrs. 1.0, 14 yrs. 1.3. Girls: 6 yrs. 1.7, 7 yrs. 1.0, 8 yrs. 

1.5, 9 yrs. 0.9, 10 yrs. 1.0, 11 yrs. 1.3, 12 yrs. 0.9, 13 yrs. 
1.5, 14 yrs. 1.4. Changes in the rate of growth causing 
asymmetrical distributions are to be expected throughout 
the periods of growth. A fundamental skewness toward 
deficient mental capacity, therefore, would be indicated 
only if it were found at maturity or at ages when the aver- 
age rate is decreasing, when the more capable individuals 
would theoretically approach relatively nearer the defi- 
cients if the latter accelerated later. 

So far as physical growth is concerned Baldwin (74, 75) 
has shown with repeated annual measurements on the 
same group of children that the period of adolescent acce- 
leration shifts from \2}4 years for the tallest boy to 16 
years for the shortest boy. For the tallest girl the maxi- 
mum height was attained at 14>£, for the shortest at 17 
years, 3 months. Maturity may be reached at 11 years 
by a tall well nourished girl, while with a short girl light 



MEASUREMENT OF MENTAL DEVELOPMENT 301 

in weight it may be delayed until 16. ' 'Children above 
medium height between the chronological ages of 6-18 
grow in stature and in physiological maturity in advance 
of those below the medium height, and they may be 
physiologically from one to four or five years older than 
those below the medium height. Those above the medium 
height have their characteristic pubescent changes and 
accelerations earlier than those below; there is a relative 
shifting of the accelerated period according to the in- 
dividuals' relative heights' ' (74). 

Doll presents evidence from the physical measurements 
of a large feeble-minded group in institutions which he 
suggests shows that the shorter among them cease grow- 
ing earlier. When the height of these feeble-minded is 
measured in relation to the Smedley percentiles of the 
height of normal children of their corresponding ages, he 
finds a correlation of — .20 between age and percentiles of 
height, the taller relative to normals being younger. He 
says: 'This confirms Goddard's similar conclusion, but 
negatives for the feeble-minded at least, the theory affirm- 
ed by some writers, that children who grow at a retarded 
rate continue their growth to a later age" (98 p. 51). 
On the contrary this minus correlation is more likely to 
mean only that the Smedley norms on school children 
are too high for the older ages because of the excess of 
taller children who remain for the high school work. 
This would give the minus correlation without supposing 
that the taller individuals continue their growth to a 
later age, as he thinks. 

Moreover, a total longer period of physical growth for 
smaller, less normal, children has been demonstrated. 
Boas (80) says: "Among the poor the period of diminish- 
ing growth which precedes adolescence is lengthened and 
the acceleration of adolescence sets in later; therefore, the 



302 DEFICIENCY AND DELINQUENCY 

whole period of growth is lengthened but the total amount 
of growth during the larger period is less than during the 
shorter period of the well- to-do' ' (80). A reversal in 
growth tendency between brain capacity and size of body, 
which is supposed when the mentally deficient are said 
to arrest earlier, would be one of the most puzzling para- 
doxes in the study of development. We should, therefore, 
be exceedingly cautious before accepting the hypothesis 
of the earlier maturity of deficient children. 

A complicated situation is presented when we come to 
represent graphically the effect on the distributions of these 
differences in growth among those of different intellectual 
capacity. In the hypothetical diagrams, Fig. 5, it is 
shown how arrest of development might be presented 
graphically in relation to the distribution curves, ability 
being measured on the same physical scale. The earlier 
acceleration and earlier maturity of those of better ability 
are indicated. The distributions are shown as skewed at all 
ages after birth. Equivalent units of mental develop- 
men at different ages can be found only in corresponding 
percentages of the groups, not in the units of the devia- 
tion or in development quotients relative to the averages 
at different ages. In other words the lowest 0.5% con- 
tinues to be an equivalent unit while — 3 S. D. measures 
different portions of the group and different portions of 
the distance from lowest to highest ability. Correspond- 
ing percentages retain one common significance, namely, 
that the same proportion of the group is ahead in the 
struggle for survival, regardless of the form of the distri- 
bution. 

It is hoped that the discussion of the statistical problems 
connected with the quantitative study of mental develop- 
ment has given more meaning to the different attempts to 
devise scales for measuring mental ability. It should be 



MEASUREMENT OF MENTAL DEVELOPMENT 303 

noted that the same relative development at different 
ages, expressed relative to the distance from lowest to 
highest ability measured in equal objective units, does 
not correspond to the same relative development meas- 
ured in percentages of the groups, as soon as the forms 
of the distributions change. The theoretical considera- 
tions show that we have available at once a perfectly 
definite and clear method of stating relative develop- 
ment in terms of corresponding percentages of corres- 
ponding groups. If the groups distribute normally these 
units are translatable into units of the standard devia- 
tion of the group. If the distributions change in sym- 
metry the only equivalent units of deficiency available 
are in terms of corresponding percentages reading from 
either end of the group. On the other hand percentile 
units are not equivalent in amount of change for the same 
distribution, so they are of most importance for compar- 
ing different age distributions of uncertain forms. 

Until we have a scale of equal objective units for men- 
tal ability, it is not possible to obtain a measure of rela- 
tive development which shall take into account the 
amount of relative change. We must be content to meas- 
ure the change in percentile rank (changes in serial 
position) of an individual relative to those of his own age. 

Having clarified our conceptions of mental develop- 
ment and brought them into harmony with certain sup- 
positions regarding the distribution of ability and its 
change from year to year, we are in a better position 
to evaluate in the following chapter the different objective 
methods of defining the borderline of feeble-mindedness. 



CHAPTER XIV. QUANTITATIVE DEFINITIONS 
OF THE BORDERLINE 

On the basis of the detailed conception of the develop- 
mental curves and distributions of ability at different 
ages, which we have been considering, we can now com- 
pare the percentage method with other quantitative 
methods of describing the borderline on developmental 
test scales. 

A. Different Forms of Quantitative Definitions 

The earliest form of the quantitative description of the 
borderline on a scale of tests, w r as in terms of a fixed unit 
of years of retardation. This was taken over apparently 
from the rough method of selecting school children to be 
examined for segregation in special classes by choosing 
those who were two or three grades behind the common 
position for children of their ages. As this amount of 
school retardation was greater for older children, an addi- 
tional year of retardation was required after the child 
had reached 9 years of age. I believe that nobody would 
seriously defend a practice of making an abrupt turning 
point of this kind, except on grounds of practical conveni- 
ence. The theory of stating the borderline in terms of 
a fixed absolute unit of retardation is so crude that it 
has now been generally superseded by methods which 
make the amount of retardation a function of the age. 

In order to relate the definition to the age of the child, 
at least during the period of growth, Stern suggested the 
' 'intelligence quotient, " consisting of the tested age divided 
by the life-age (188). This has been adopted by Kuhl- 
mann with his revision of the Binet scale (139) and by 
Terman with the new Stanford scale (197). With the 

(304) 



QUANTITATIVE DEFINITIONS OF BORDERLINE 305 

Point scale Yerkes utilized a similar ratio method for 
stating borderlines by what he calls a "coefficient of in- 
telligence. " He defines it as "the ratio of an individual's 
point-scale score to the expected score, or norm" (226, 
p. 595). Haines also uses these coefficients, dividing the 
individual 's score on the Point scale by the average number 
of points scored by those of his age (26). The difference 
between the " quotient' ' and the "coefficient" seems to be 
mainly empirical since they are theoretically alike in 
principle provided the scales by which they are determined 
are composed of equal units. Empirically, however, the 
units of the point scale would have to be compared with 
the 0.1 year units of the Binet scale to determine which 
showed the greater uniformity within its own scale. The 
coefficient has an advantage over the quotient in that the 
scale norms for the different ages would automatically 
become readjusted with additional data, and that phys- 
iological age norms could be more readily stated if they 
were ever available. 

The suggestion of defining the borderline of tested de- 
ficiency in terms of a multiple of the standard deviation 
of ability of children who are efficient in school was made 
by Pearson in 1914. Tested inefficients did not with him 
include all inefficients, as he recognized other sources of 
deficiency. He had previously suggested a scale of mental 
ability in units called "mentaces", 100 of which were 
equivalent to a unit of the standard deviation of all ability 
assumed to be normally distributed. On this scale of 
mentaces the imbeciles were 300 mentaces or more below 
average ability and would be expected to occur once among 
1000 individuals chosen at random. Very dull, including 
some mentally defective individuals, were also to be 
found from 208 to 300 mentaces below the average (166, 
p. 109). Defining the borderline in terms of the deviation 



306 DEFICIENCY AND DELINQUENCY 

of a normal population was definitely forecasted by Nors- 
worthy, although she did not specifically discuss the prob- 
lem of the borderline. She indicated that if children tested 
below - 5 P. E . , they might be regarded as outside the normal 
group. 

The following quotation from Pearson will make the 
method of stating the borderline in terms of a multiple 
of the deviation clearer: 

4 'Now the question is, what we mean by a 'special or differentiated 
race': I should define it to mean that we could not obtain it by any 
selection from the large mass of the normal material. Now in the case 
of the mentally defective, we could easily obtain children of their height, 
weight, and temperature among the normals. We could, out of 50,000 
normal children, obtain children practically with the same powers of 
perception and memory as the feeble-minded, as judged by Norsworthy's 
data. But not out of 50,000, nor out of 100,000 normal children, could 
we obtain children with the same defect of intelligence as some 50% 
of the feeble-minded children. In other words, when the deviation of a 
so-called feeble-minded child from the average intelligence of a normal- 
minded child is six times the quartile or probable deviation of the group 
of normal children of the same age, it falls practically outside the risk 
of being an extreme variation of the normal population. Now six times 
the quartile variation is almost exactly four times the standard devia- 
tion or the variability in intelligence of the normal child, and in the next 
material I am going to discuss [Jaeder holm's], we have shown that the 
standard deviation in intelligence of the normal child is just about one 
year of mental growth" (164, p. 35). 

With the Jaederholm data obtained in testing children 
in the regular and in the special classes in Stockholm by 
a modified form of the Binet scale, Pearson found that a 
year of excess or defect in intelligence was practically a 
uniform unit from 7 to 12 years of age and was about 
equivalent to the standard deviation of normal children 
measured in these year units. He, therefore, uses a year 
unit and the standard deviation as interchangeable for 
these data. He does not, however, always make it clear 



QUANTITATIVE DEFINITIONS OF BORDERLINE 307 

whether he means that the equivalence of the year units 
is determined by the standard deviation of the children 
of all these ages grouped together in one distribution, as it 
is in determining the regression lines, or by the equivalence 
of the standard deviations of the separate ages, especially 
when these two deviations are not equal in terms of the 
year units on the scale. I shall assume, however, that he 
would use the deviations of the separate years in case of 
such an inequality of the two concepts. 

The quotation from Pearson, which we have given above, 
indicates that he would determine the borderline on the 
scale by the standard deviation of 'normal' children. In 
his case he actually used children who were efficient in 
school, as contrasted with those in special classes. On 
the other hand, he argues at length that all mental ability ,- 
including that of the social inefficients, is distributed in 
the form of the normal curve (167). Under this assump- 
tion it is, therefore, little theoretical change in his position 
to suppose that the borderline might be described in terms 
of the standard deviation of a random sample of the popu- 
lation. Defining the borderline in terms of a multiple 
of the deviation of a random sample at each age thus 
becomes directly comparable with the other forms of the 
quantitative definition, supposing that all refer to condi- 
tions to be found in a completely random sample. It is 
in this sense that I shall refer to the method of defining the 
borderline in terms of a multiple of the deviation. 

The percentage method of defining the borderline seems 
to have been the spontaneous natural working out of the 
problem in the minds of several investigators. At the 
same time that I suggested this method in a paper before 
the American Psychological Association (151) Pintner 
and Paterson had prepared a paper suggesting a percentage 
definition of feeble-mindedness (44) and Terman had work- 



308 DEFICIENCY AND DELINQUENCY 

ed out his use of the quotient so that the borderline in 
terms of the quotient was given equivalent form in terms 
of percentage. Nobody, however, seems to have attempt- 
ed to work out the details of the method as in the present 
monograph. 

As a point of detail it is to be remembered that in translating per- 
centages into terms of the deviation, the size of the group for which the 
percentages are determined is important if the groups are small, since 
the same percentage lies above slightly different multiples of the stand- 
ard deviation with different sized groups. On this point the reader may 
see a paper by Cajori and the references cited there (86). 

B. Common Characteristics of Quantitative Defi- 
nitions 

In distinction from qualitative methods of describing 
the mentally deficient, all quantitative definitions assume 
that those of deficient mentality do not represent a differ- 
ent species of mind; but that they are only the extreme 
representatives of a condition of mental ability which 
grades up gradually to medium ability. The deficient 
are not an anomalous group such as we find with some 
mental diseases. Except for the comparatively rare 
cases of traumatic or febrile origin, the deficient indivi- 
dual is a healthy individual so far as his nervous system 
is concerned, even though his capacity for brain activity 
is below that of those who socially survive. They are 
not as a group abnormal in the sense of diseased, but 
only unusual in the sense of being extreme variations 
from medium ability in a distribution which is unin- 
terrupted in continuity. This distinction has been 
fully discussed by Goring in his work on The English Con- 
vict, which those who are interested in a full mathematical 
discussion of the significance of mental deficiency are urged 
to read. 



QUANTITATIVE DEFINITIONS OF BORDERLINE 309 

Schmidt urges that the deficients are qualitatively different in being 
"unable to plan", and then suggests tests which most markedly bring 
out this distinction between deficient and normal children (178). As I 
have said before, however, this seems rather to be a failure to recognize 
that such an attempt to find tests which "qualitatively" distinguish the 
two groups is only an effort to pick those tests which best make measur- 
able the differences between individuals at the extreme of mental ability. 
As such it is a valuable contribution to this problem. If it is intended as 
an attempt to set up a qualitative distinction in a mathematical or 
biological sense, between deficient and passable ability, it seems to me 
wholly to fail. As I take it, a "qualitative" distinction with Schmidt is 
only a bigger quantitative distinction and is intended only to mean this. 

None of those who advocate quantitative definitions 
would contend, I believe, as some of their opponents seem 
to think, that such definitions afford a final diagnosis for 
particular cases. In attempting to place the borderlines 
on a scale of tests, this is always done with the clear recog- 
nition that such borders are only symptomatic of defi- 
ciency. The diagnosis of " social inefficiency, " to use Pear- 
son's term, rests upon many facts among which the test 
result is only one, albeit the most important. 

Other characteristics which each of the above quantita- 
tive definitions, except that of a constant absolute amount 
of deficiency, have in common, or might easily have if 
they were stated in their best forms, include the possibility 
of adaptation to any developmental scale, the suggestion 
of borderlines for both the mature and immature, the 
distinction of a group which might be regarded as pre- 
sumably deficient from one that was of better but doubtful 
ability and of this from a still better group which was 
presumably socially efficient. 

Perhaps the most curious and important thing about 
these definitions is that they are all substantially identical, 
except in their terminology so long as general mental 
capacity is found to distribute in the form of the normal 
probability curve and to extend to absolute zero ability 



310 DEFICIENCY AND DELINQUENCY 

at each age. This can easily be seen by comparing the 
distribution curves in Fig. 3. The position of the per- 
centage borderline would always represent the same dis- 
tance from the average in terms of the standard deviation 
of each age and the same ratio when the life-age of arrest 
of development had been determined as the largest di- 
visor. Under these conditions, therefore, these main 
statements of the quantitative definition agree in suppos- 
ing that the same proportion of the individuals of each 
life-age would test deficient. Those who advocate any 
of these quantitative definitions logically commit them- 
selves to assuming that the percentage of deficients at each 
age is practically constant, unless they suppose the sym- 
metry of distribution varies or does not extend to the same 
zero point. 

If the distributions do not extend to the same zero 
points of lowest ability on an objective scale (see Fig. 5), 
the ratio is clearly at a disadvantage compared with either 
of the other methods, since it assumes that the same per- 
centage of average ability is an equivalent measure. This 
does not hold when the lowest ability at different ages is 
not at the same point on the scale of objective units. 
For example, .7 of an average 100 units above is not 
equivalent to .7 of an average 150 points above a zero 
ability of 30 points on tfe objective scale. The idea of 
regarding percentages of averages as equivalent is there- 
fore generally avoided in mental measurement. In case 
the position of the absolute zero points of ability may be 
different, the distance from the average should be stated 
in terms of the deviation. In this respect the method of 
the deviation or the lowest percentage are equally good so 
long as the form of distribution does not change. 



QUANTITATIVE DEFINITIONS OF BORDERLINE 311 

C. Practical Advantages of the Percentage Method 

1. With the percentages fixed at the lowest 0.5% as 
presumably deficient and the next 1.0% doubtful, these 
borderlines for tested deficiency have the advantage of 
being more conservative than those at present advocated. 
On the basis of our empirical knowledge this is an import- 
ant reason for urging borderlines on the scales at least as 
low as those suggested herein. Disregarding the ex- 
tremely high borderlines which have fallen into disuse, we 
still find that social deficiency is often presumed for those 
testing above the lowest 1%. With the new Stanford 
scale, Terman presumes "definite feeble-mindedness ,, be- 
low an Intelligence Quotient of .70, below which he finds 
that 1% of 1000 unselected children fell. I Q's from .70 
to .80 would include his uncertain group, which he describes 
as "border-line deficiency, sometimes classified as dull- 
ness, often as feeble-mindedness ,, (57, p. 79). His tables 
show 5% below an I Q of .78. We have no results with 
a random group of adults by which to judge how many 
would be below these borders. When the I Q has been 
applied to scores with other scales a larger percentage has 
often been found to be excluded. Fernald has shown that 
Haines' suggestion of a coefficient of .75 with the Point scale 
would exclude 16% of 100 Cincinnati girls selected at 
random from among those who left school at 14 years to 
go to work (16). 

Unless the examiner wishes to assume that social in- 
efficiency is more frequent than it has been demonstrated 
by the practical tests of life, the success of those who have 
low quotients should make him exceedingly cautious about 
accepting the various borderlines which have been sug- 
gested by those who have not tested their criteria by the 
percentage method. It is not merely that the border- 
lines should be lowered, but that they should be lowered 



312 DEFICIENCY AND DELINQUENCY 

under some consistent plan so that we should know as 
much as is possible about their significance in the predic- 
tion of ultimate social inefficiency, and that we should be 
able to readjust them on the basis of new data or to new 
scales. 

With the Point scale Yerkes and Wood say regarding 
"the coefficient of intelligence .70, which we accept as the 
upper limit of intellectual inadequacy or inferiority": 
"Our data indicate that grades of intellectual ability 
measured by the coefficient .70 or less are socially burden- 
some, ineffective, and usually a menace to racial welfare" 
(226). With the most reliable part of their data, that 
for children from 8-13, this coefficient excludes the lowest 
8.39%. Moreover, the lowest group for which they sug- 
gest a borderline, the dependents, falls at .50 or below and 
includes 1.05%. 

2. A second practical advantage of the percentage bord- 
erlines on the scale is that they make no assumption as to 
the uniformity of the norms for the different ages. Except 
for the Stanford and the Jaederholm scales, there is little 
evidence that the age norms exclude equivalent portions 
of the children at the different life ages. 

Goddard's Table I gives the data from which the follow- 
ing percentages of those who pass the norm are calculated, 
not counting those above 11 years, since the older groups 
are clearly affected by selection: — 5 yrs., 88%; 6 yrs., 
79%; 7 yrs., 81%; 8 yrs., 51%; 9 yrs., 60%; 10 yrs., 73%; 
11 yrs., 44%. Kuhlmann's figures when using his own 
revised scale with public school children including the 
seventh grade, are: — 6 yrs., 100%; 7 yrs., 95%; 8 yrs., 
90%; 9 yrs., 87%; 10 yrs., 81%; 11 yrs., 80%; 12 yrs., 
57%. It is clear that any change in the test norm from 
age to age must disturb the quotient which is based on these 
norms, although it would not affect the intelligence co- 
efficient with the Point scale. 



QUANTITATIVE DEFINITIONS OF BORDERLINE 313 

3. A third advantage of the percentage method arises 
from the fact that we cannot presume that the same ratio 
in terms of the scale units will exclude the same degrees 
of ability at different ages even when the norms for these 
ages are properly adjusted. The earlier results with the 
Stanford revision show a large variation as to the per- 
centage excluded by the same I Q at different ages. 
For example, an I Q of .76 would have shut out 1% of 
117 non-selected 6-year-olds, 2% of 113 9-year-olds and 
7% of 98 13-year-olds. The lowest 1% of the last group 
was below a borderline of .66 (197). 

With widely varying norms of the other scales, the I 
Q borderlines show much greater variation. In a recent 
review of the evidence, including Descoeudres' report (96) 
on retesting the same children for several years Stern 
recognizes that an I Q index is not constant after 12 
years (187). Doll records decided changes in quotients 
for the same individual at different ages (99). So far as 
the 1908 scale is concerned, using Goddard's data, our 
Table V shows that at five years of age the lowest 1.8% 
would fall at or below a quotient of .40, at eight years the 
lowest 1.9% would show a quotient of .62 or less, and at 
15 years the lowest 2.8% fall below a quotient of .75. The 
rough tentative approximation of scale limits which I 
have suggested for the lowest 1.5% shows that a series of 
quotients for children from 5 to 15 years of age would be 
below .75 at every age and below .65 for half of these ages. 
For the presumably deficient group the quotients would 
be still lower in order to be as conservative as the border- 
lines that I have suggested with the Binet scale as at pres- 
ent standardized. 

With the coefficient of intelligence and the Point scale, 
the Yerkes and Wood data show that their borderline of 
.70 excluded 13% of 196 children 8 and 9 years of age, 



314 DEFICIENCY AND DELINQUENCY 

while it excluded only 5% of each of the next two groups 
of double ages. With the group of 237 18-year-old Cin- 
cinnati working girls it excluded only 3% (226). 

The data at present available thus indicate that we 
should not expect to find the same ratio at different ages 
excluding similar percentages. If the ratios have a value 
for comparing individuals of different ages, they seem to 
fluctuate so decidedly from age to age that they can hardly 
be trusted for stating the borderlines of deficiency without 
empirical confirmation for each age. 

Pearson found that the children of the older ages in 
the special classes were more and more deficient, measur- 
ed in terms of the standard deviation of the normal 
group. This shift on the average was four months of 
mental age downward for each year of life during the 
period 7-14 which he studied. It makes uncertain the 
definition of the borderline in terms of a constant multiple 
of the deviation or of a constant quotient, unless this shift 
is shown to be due to imperfections of the tests which can 
be corrected, or to changes in the selection of the tested 
groups at advanced ages. 

Pearson 's suggestion of — 4 S. D. as a borderline with the 
Jaederholm data gives some very curious results with the 
group of children in the special schools at Stockholm. 
Under his interpretation at life-ages 8-11 from to 5.2% 
of the pupils in these classes would be regarded as deficient, 
while for life-ages 12-14, 15.2% to 44.4% are beyond — 4 
S. D. In passing it is to be noted that if one accepted 
Pearson's suggestion that the borderline should be fixed 
at — 4 S. D., in case the distribution of mental capacity 
were strictly normal, only four children in 100,000 would be 
found deficient, according to the probability tables. 

With the method of the standard deviation it would be 
necessary either to show that the deviation was constant 



QUANTITATIVE DEFINITIONS OF BORDERLINE 315 

in terms of the year units or else to restate the borderline 
for different ages in terms of the scale units. The irregu- 
larity of the norms with the Binet scale could also be allow- 
ed for, of course, by stating different quotients for the 
different ages, but when this readjustment is required for 
either the ratio or the deviation in terms of the scale units, 
these methods lose all their advantage of simplicity. In- 
stead of one ratio or one multiple of the years of devia- 
tion, we might have a different statement for each life-age. 
With the percentage method there would be only one 
statement of the borderline for all ages in terms of per- 
centage, although the scale positions change which shut 
out the same lowest percentage. 

4. All the quotient methods of defining the borderline 
encounter a serious practical difficulty in fixing the border- 
line for the mature, so that it will be equivalent to that 
for the immature. With the Stanford scale in calculating 
the quotient for adults, no divisor is used over 16 years. 
Yerkes and Bridges also think that this is about the time 
that the development of capacity ceases. Kuhlmann and 
others use 15 as the highest divisor. Wallin objects to 
either of these ages being used as the age of arrest of mental 
development (15 9 p. 67). Both the methods of the stand- 
ard deviation and percentage have a similar difficulty, 
in that the borderline for the mature has to be empirically 
determined on a test scale. In this dilemma, however, 
the data collected with the random group of 15-year-olds 
in Minneapolis and published in the present study, places 
the borderline for the mature on either the 1908 or 1911 
Binet scale in a much safer position, so far as empirical 
data is concerned, than the borderline for the mature for 
any other scale. This is true whether that borderline be 
then stated in terms of either the quotient or percentage 
methods. Translated into terms of the quotient, our per- 



316 DEFICIENCY AND DELINQUENCY 

centage borderlines for the mature with these scales, be- 
low X for presumably deficient and below XI for the un- 
certain, would amount to quotients .60 and .66 on the 
basis of our findings with this random group of children 
who have presumably about reached adult development. 
Pearson does not attempt to define any borderline for the 
adults on the basis of the deviation, since Jaederholm 
tested only children. Moreover, this is not possible em- 
pirically with our group of 15-year-olds, since we tested 
only the lower extreme of this group. 

Unfortunately, the borderlines of the mature for the 
Stanford and other scales depend upon empirical results 
obtained not with random groups, but upon a composite 
of selected groups of adults built up by the investigator 
on an estimate that this combined group represents a 
random selection among those with a typical advance in 
development, an almost superhuman task. Fortunately 
the empirical determination of this borderline for the 
mature might be improved later by obtaining data on 
less selected groups. The clearer significance of the empir- 
ical data for the borderline for the mature which I have 
presented for the Binet 1908 and 1911 scales from a random 
group of 15-year-olds seems to be an important practical 
advantage. It provides an empirical basis for judging the 
implication of test results with adults. It gives adults 
the benefit of the doubt if they improve after 15 years of 
age. 

5. Compared as to their popular significance, there is no 
doubt that the lowest 0.5% of the individuals of a parti- 
cular age has very much more significance to those not 
familiar with detailed statistical practise than a coefficient 
or a multiple of the standard deviation. A statement that 
an adult has only the tested ability of a child of 7 years is 
certainly much more impressive than his score in other 



QUANTITATIVE DEFINITIONS OF BORDERLINE 317 

quantitative terms. It will probably always be desirable, 
therefore, to supplement any other method of scoring by 
a statement of the individual's test age. 

D. Theoretical Advantage of the Percentage 

Method with Changes in the Form of the 

Distributions 

With our present series of tests, the percentage method 
will best provide a concept of the equivalence of the border- 
lines at different ages provided the form of the distribution 
does not remain uniform. I discussed this question briefly 
in connection with units of measurement. In considering 
curves of development, I assembled some of the evidence 
which makes the assumption of normal distribution or 
even of a constant skewness at least uncertain. In my 
opinion the weight of the evidence is against the hypo- 
thesis that the distributions retain a constant form during 
the period of development. If this were clearly demon- 
strated, both the ratio methods and deviation would fail 
to express equivalent borderlines for the different ages 
with the Binet scales. A fixed multiple of the standard 
deviation or a fixed quotient would exclude different per- 
centages of the population at each age when the skewness 
varied. By reference to Figures 3 and 5, it can be seen 
that, if our physical units in which we expressed the meas- 
urement were uniform and ability always extended to the 
same absolute zero point, it is true that .01 of the physical 
units reached by the best at each age would be the same 
relative amount of ability of the best at each age, stated 
in physical units, regardless of the form of the distributions. 
Such a concept, however, has an unknown biological or 
social significance so far as I can see, except for a constant 
form of distribution. The same relative physical score 
compared with the highest at each age, theoretically 



318 DEFICIENCY AND DELINQUENCY 

might exclude the lowest 40% of one age group, for ex- 
ample, and only 10% of another group provided the dis- 
tribution varied enough in form. The concept of the 
same relative amount of ability measured in physical 
units, so soon as the form of distribution varies from age 
to age, thus loses significance in terms of the struggle for 
existence. In that struggle, a vital question is — do the 
individuals at different ages have to struggle to overcome 
the same relative number of opponents of better ability 
at their age? If they do, the individuals might properly 
be regarded as in equivalent positions in the struggle for 
social survival, disregarding how far the next better indi- 
vidual is above them on the objective scale. This is the 
concept accepted by the percentage definition of the bord- 
erline as the best available under uncertain forms of dis- 
tribution. 

The recent rapid perfection of objective scales to meas- 
ure educational products, like ability in handwriting, etc., 
in equal units running to an absolute zero of ability, sug- 
gests that it might be possible ultimately to state the 
borderline of deficiency in terms of the same relative ob- 
jective distance between the best and zero ability at each 
age on a scale of general ability. This ideal could be ap- 
proached, for example, with the Sylvester form-board test 
in which the units are seconds required to complete the 
same task, if we could agree upon a maximum number of 
seconds without success which should mean no ability, and 
if this zero should remain the same at each age. It would 
only be necessary to take, for example, the best position 
or the median or the upper quartile at each age as the other 
point of reference. We could then say that a borderline 
in physical units was always, for example, .01 of the median 
record at each age above zero. Such a method would 
provide relatively equal objective borderlines at each age 



QUANTITATIVE DEFINITIONS OF BORDERLINE 319 

and it would afford a measure which would take into ac- 
count the ability of the individuals to be competed against 
instead of merely counting them as the percentage method 
must. It would be better than a description in units of 
the standard deviation in that its significance would be 
more easily understood if the form of distribution varied 
with age. 

To demonstrate its worth, however, this method of 
defining the borderline in terms of the same proportion of 
the physical difference between zero and the median at each 
age, would also have to provide a better prediction of 
ultimate social failure. It would have to be shown that 
individuals below the relative objective borderline at 
maturity were below the same relative objective border- 
line during immaturity. Moreover, it would have to be 
shown that this relationship was closer than it would be 
with percentile records. It is a form of this relative ob- 
jective measurement which Otis advocates in his "ab- 
solute intelligence quotient," which he proposes as log- 
ically the best measure of ability. It consists of the 
ratio of the score of the individual measured in equal 
absolute units of intelligence, divided by his age (163). 

While a relative objective borderline might under 
certain circumstances afford a better criterion than the 
same lowest percentage of individuals, there are two very 
serious practical difficulties which at present make it 
impossible. In the first place, with the exception of a few 
motor tests, there are no test results with children of differ- 
ent ages measured in terms of equal objective units for 
the same task. Even if the Binet year units are equal, as 
applied to the same task, there is no accurate means of 
dividing the year units into smaller physical units on the 
basis of scores with the tests. This makes the use of the 
Binet scale impossible and we should be forced back upon 



320 DEFICIENCY AND DELINQUENCY 

such tests as the form-board, the ergograph, etc., for which 
we should have to agree upon an absolute zero of ability. 
Moreover, mental tests do not lend themselves to measure- 
ment in terms merely of rapidity in doing the same task 
or in terms of other equal physical units since the quality 
of the work also has to be evaluated and this is usually 
done in units assumed arbitrarily to measure equivalent 
degrees of perfection. 

The second practical difficulty which at present makes a 
relative objective borderline impossible is that we know 
nothing as to the prediction of social failure and success 
from relative positions on the objective scale used even 
with the few isolated tests that might be made available. 
Until we have data on this question, as well as scales of 
tests for native ability that are measurable to zero ability 
in objective terms, the percentage method affords the only 
available way of stating equivalent borderlines when the 
form of distribution changes. 

If the age of arrest of development shifts either earlier 
or later with different degrees of capacity, then there 
seems to be no logical escape from a change in the form 
of distribution. Stern recognized this when he concluded 
that idiots reach an arrest of development earlier than 
those better endowed, so he stated that his quotient would 
not hold for them. He said: 

/'The feeble-minded child, it must be remembered, not 
only has a slower rate of development than the normal 
child, but also reaches a stage of arrest at an age when the 
normal child's intelligence is still pushing forward in its 
development. At this time, then,, the cleft between the 
two will be markedly widened. 

"From this consideration it follows that the mental 
quotient can hold good as an index of feeble-mindedness 
only during that period when the development of the feeble- 
minded individual is still in progress. It is for this reason 



QUANTITATIVE DEFINITIONS OF BORDERLINE 321 

that there is no use in calculating the quotient for idiots, 
because, in their case the stage of arrested development has 
been entered upon long before the ages at which they are 
being subjected to examination" (188). 

Perhaps the most interesting characteristic of the per- 
centage method is that it automatically adjusts itself to 
any form of distribution. In case the distributions of 
ability turn out to be normal for each age and the arrests 
of development for different degrees of ability distribute 
alike, then the borderline fixed by the percentage method 
becomes identical with the corresponding borderlines by 
the quotient, deviation, or relative objective distance. 
It can be directly translated into a quotient or a multiple 
of the standard deviation. This fact affords a good check 
upon the empirical borderlines fixed by the percentage 
method for different ages. If the distribution is normal, 
the lowest 1.5% and 0.5% would be identical with — 2.17 
S. D. and —2.575 S. D. in samples of 10,000 cases. We 
may check these percentage borderlines by Goddard's 
results for ages 5-11 tested with the 1908 Binet scale. 
I have given the standard deviation for the ages 5-11 with 
this data in Chap. XIII a, 2. Applying the criterion of 
2.575 S. D. to these deviations, we find that to be in the 
lowest 0.5%, if the distribution were normal, would be 
about a year less of deficiency than we have suggested, 
while Pearson's borderline of — 4 S. D. would be close to 
that we suggest. The empirical data thus suggest that 
the assumption of a normal distribution is faulty at the 
borderline or else Goddard's data is incorrect for fixing 
the limits on the scales. I have already given the evidence 
for supposing that the distribution is skewed during the 
years of growth. 

When approximately random samples are not available, 
a multiple of the deviation of an efficient group such as 



322 DEFICIENCY AND DELINQUENCY 

— 4 S. D. at the particular age seems to afford a practical 
way of discovering a tentative borderline until a random 
sample can be measured. The serious theoretical objec- 
tions to such a procedure as a regular method is that the 
efficient group would be selected by the subjective stand- 
ard of somebody's opinion and that the form of distri- 
bution of ability may vary from age to age. 

Recalling the practical advantages of the percentage 
method which we enumerated in the preceding section, 
we can now better understand the value of a method that 
is not disturbed by the form of distribution of mental 
capacity which may ultimately be found to prevail at 
different ages. It is safer at present to assume that the 
distributions do change enough in form at the lower end 
seriously to affect the borderlines of deficiency as defined by 
other methods. If, however, the form of distribution re- 
mains uniform, it would first be necessary for those advo- 
cating the use of any of the other quantitative definitions 
to show that the units of their scales are equal under some 
reasonable hypothesis. A ratio or a deviation statable 
only in scale units which are not demonstrably equal is a 
hazard, with the chances badly weighted against its re- 
liability. So far as both the Binet and the Point scales 
are concerned we have found that the units are not equal. 
A quotient or coefficient arrived at by assuming their 
equality is sure to mean seriously erroneous fluctuations in 
the borderlines. 

Referring to the percentage method, Yerkes and Wood 
say: ' 'Frequency of occurrence is unquestionably a use- 
ful datum, which should be presented, if not instead of, 
then in addition to, certain other statistical indices which 
possess greater scientific value' ' (226). These other in- 
dices require both equal scale units and uniform distribu- 
tions from age to age. The ratio and deviation methods 



QUANTITATIVE DEFINITIONS OF BORDERLINE 323 

fail at present in both of these particulars, so that it seems 
necessary to depend upon the percentage definition of 
tested deficiency, incomplete as that may be. 

This leaves us in the unfortunate situation that the 
borderline positions on the scale will have to be stated 
separately for each age and will have to be found empiri- 
cally. Moreover, we shall need to determine more accu- 
rately in what lowest percentage an individual must test 
in order reasonably to predict that he will require social 
care for the good of himself and society. 

As soon as anybody can discover a means of defining 
the borderline, which is equally accurate and significant, 
and which, in addition to counting the proportion of 
better individuals to be met in the competition of life, will 
also evaluate the distance they are above the borderline, 
we all shall be eager to accept this better criterion of de- 
ficiency. A form which it might take is that of relative 
objective distance between zero and median ability. If 
measurable in equal objective units, this would be inde- 
pendent of the form of distribution and would improve 
the quantitative description of equivalent deficiency, pro- 
vided that it also forecasted future social failure as well 
as the percentage method. 

What form of stating the borderline of tested deficiency 
may ultimately meet with approval, a verbal definition of 
feeble-mindedness will never remain an ideal scientific 
statement until it finds expression in quantitative terms. 



BIBLIOGRAPHY ON TESTED DELINQUENTS* 

1. Baldwin, Bird T. The Learning of Delinquent 
Adolescent Girls as shown by a Substitution Test. J. of 
Educ. Psychol, 1913, 4, 317-332. 

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*Additional references on tested delinquents will be found as foot- 
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(324) 



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1913, 48, 214-217. 

171. Rhoades, Mabel Carter. A Case Study of De- 
linquent Boys in the Juvenile Court of Chicago. Univ. of 
Chicago Press, 1907, pp. 25. 

172. Rogers, A. C. Classification of the Feeble-Minded 
Based on Mental Age. Bull, of Amer. Acad, of Med., 1912. 
13. 

173. Rogers, A. C. Discussion of the Mentally De- 
fective and the Courts. J. of Psycho-Asthenics, 1910, 15, 
58. 



BIBLIOGRAPHY 339 

174. Rosanoff, Isabel R. and Rosanoff, A. J. A 
Study of Association in Children. Psychol. Rev., 1913, 
20, 43-89. 

175. Rossolimo, G. Die psychologischen Profile, zur 
Methodik der quantitativen Untersuchung der psychischen 
Vorganze in normalen und pathologischen Fallen. Klinik 
f. psychische u. nevbse Krankeiten, 1911, 6, Heft. 2. 

176. Rybakow, Th. Atlas zur psychologischen Unter- 
suchungen auf gesund und geistes Kranken. 

177. Schaefer, H. Allgemeine gerichtliche Psychiatrie 
fur Juristen, Mediziner und Padogogen. Ernst Hoffman, 
Berlin, 1910. 

178. Schmidt, Clara. Standardization of Tests for De- 
fective Children. Psychol. Monog., 1915, 19, No. 3. 

179. Schmidt, Clara. The Binet-Simon Tests of Mental 
Ability t Discussion and Criticism. Ped. Sem., 1912, 19 
186-200. 

180. Schwegler, Raymond A. A Teacher's Manual for 
the use of the Binet-Simon Scale of Intelligence. Kansas 
State Printing Office, Topeka, 1914, pp. 56. 

181. Shuttleworth, G. E. and Potts, W. A. Ment- 
ally Deficient Children. 3rd Ed. Blakistons Son & Co., 
1910, pp. 236. 

182. Simon, Th. Measurement of Intelligence. Eugen- 
ics. Rev., 1915, 6,. 291-307. 

183. Spaulding, Edith R. The Results of Mental and 
Physical Examinations of Four Hundred Women Offenders, 
with Particular Reference to their Treatment during Com- 
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717. 

184. Spearman, C. The Heredity of Abilities. Eugen- 
ics Review, 1914, 6, 219-237. 

185. Spearman, C. The Theory of Two Factors. Psy- 
chol. Rev., 1914, 21, 101-115. 



340 DEFICIENCY AND DELINQUENCY 

186. Starch, Daniel. The Measurement of Efficiency 
in Spelling and the Overlapping of Grades in Combined 
Measurements of Reading, Writing and Spelling. J. of Educ. 
Psychol., 1915, 6, 167-186. 

187. Stern, William. Der Intelligenz quotient ah Mass 
der kindlichen Intelligenz, inbesondere der unter normalen, 
Zsch.f. angew Psychol., 1916, 11, 1-18. 

188. Stern, William. Psychological Methods of Test- 
ing Intelligence. Trans, by G. M. Whipple. Psychol. 
Monographs, Warwick and York, Baltimore, 1914. 

189. Strayer, George Drayton. Age and Grade 
Census of Schools and Colleges. Bull, of the U. S. Bureau 
of Educ, 1911, No. 5, pp. 144. 

190. Strong, Alice C. Three Hundred Fifty White and 
Colored Children Measured by the Binet-Simon Measuring 
Scale of Intelligence. A Comparative Study. Ped. Sem., 

1913, 20, 485-515. 

191. Sylvester, Reuel Hall. The Form Board Test. 
Psychol. Monog., 1913, No. 65, pp. 56. 

192. Terman, Lewis M. The Binet Scale and the Diag- 
nosis of Feeble-Mindedness. J. of Crim. Law and Criminol., 
1916, 4, 530-543. 

193. Terman, Lewis M. The Mental Hygiene of Ex- 
ceptional Children. Ped. Sem., 1915, 22, 537-539. 

194. Terman, Lewis M. The Significance of Intelli- 
gence Tests for Mental Hygiene. J. of Psycho- Asthenics, 

1914, 18, 119-127. 

195. Terman, Lewis M. and Childs, H. G. A Tenta- 
tive Revision and Extension of the Binet-Simon Measuring 
Scale of Intelligence. J. of Educ. Psychol., 1912, 3, 61-74, 
133-143, 198-208, 277-289. 

196. Terman, Lewis M. and Knollin, H. E. Some 
Problems Relating to the Detection of Borderline Cases of 
Mental Deficiency. J. of Psycho-Asthenics, 1915, 20, 
1-15. 



BIBLIOGRAPHY 341 

197. Terman, Lewis M.; Lyman, Grace; Ordahl, 
George; Galbreath, Neva; and Talbert, Wilford. 
The Stanford Revision of the Binet-Simon Scale, and Some 
Results from its Application to One Thousand Non-Selected 
Children. J. of Educ. Psychol., 1915, 6, 551-564. 

198. Thorndike, Edward L. Educational Psychology. 
Revised Edition. Columbia, Teachers' College, N. Y. 
City, 1914, pp. x 4- 408. 

199. Thorndike, Edward L. Measurement of Twins. 
Archives of Psychol., 1905, No. 1, pp. 64. 

200. Thorndike, Edward L. The Significance of the 
Binet Mental Ages. Psychol. Clinic, 1914, 8, 185-189. 

201. Towne, Clara H. Mental Types of Juvenile De- 
linquents, Considered in Relation to Treatment. J. of Crim. 
Law and Criminol., 1913, 4, 83-89. 

202. Travis, Thomas. The Young Malefactor. N. Y., 
1908. 

203. Treadway, Walter L. Care of Mental Defec- 
tives, the Insane, and Alcoholics in Springfield, Illinois. 
The Springfield Survey, No. VIII, 1914, pp. ix + 46. 

204. Tredgold, A. F. Mental Deficiency {Amentia). 
2nd Ed. Revised and Enlarged. Bailliere, Tindall & Cox, 
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205. United States Bureau of Census, Dept. of Com- 
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1914. 

206. United States Bureau of Census, Dept. of Commerce. 
U. S. Special Report of Census Office on Mortality. Gov- 
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207. United States Bureau of Census, Department of 
Commerce. United States Life Tables, 1910. Prepared 
under the Supervision of James W. Glover, Government 
Printing Office, 1916. 

208. United States Commissioner of Education, Annual 
Report, 1914. 



342 DEFICIENCY AND DELINQUENCY 

209. Van Sickle, James H; Witmer, Lightner; Ayres, 
Leonard P. Provisions for Exceptional Children in Public 
Schools. Bull, of U. S. Bur. of Educ, 1911, No. 14, pp. 92. 

210. Wallin, J. E. Wallace. Eight Months of Psycho- 
Clinical Research at the New Jersey State Village for Epilep- 
tics, with Some Results for the Binet-Simon Testing. Trans, 
of the Nat. Assoc, for the Study of Epilepsy, 1911, 29-43. 

211. Wallin, J. E. Wallace. Mental Health of the 
School Child. Yale Univ. Press, 1914, pp. 463 + ix. 

212. Wallin, J. E. Wallace. Psycho-Motor Norms for 
Practical Diagnosis. Psychol. Monog., 1916, 22, No. 2, 
pp. 102. 

213. Wallin, J. E. Wallace. Re-Averments Respect- 
ing Psycho-Clinical Norms and Scales of Development. 
Psycho. Clinic, 1913, 7, 89-97. 

214. Wallin, J. E. Wallace. Who is Feeble-Minded? 
J. of Cri.LawandCriminol., 1915, 6, 706-716. 

215. Wallin, J. E. Wallace. Who is Feeble-Minded? 
A Reply to Mr. Kohs. J. of Crim. Law and Criminol., 
1916, 7, 56-78. 

216. Wallin, J. E. Wallace, and Kohs, Samuel C. 
Who is Feeble-Minded? A Rejoinder and a Rebuttal. J. 
of Crim. Law and Criminol., 7, 219-226. 

217. Webb, E. Character and Intelligence. Brit. J. of 
Psychol., Monog. Sup., 1915, 3, pp. ix + 99. 

218. Weidensell, Jean. Criminology and Delinquency. 
Annual Summary, Psychol. Bull., 1913, 10, 230-236. 

219. Weyandt, Prof. Dr. Ein Schwachsinns-Pru- 
fungskasten von Prof. Dr. Weyandt. Zsch. f. Erforschung 
und Behandlung des jugendlichen Schwachsinns, 1910, 
4, Reprint by P. Johannes Muller, Charlottenburg 5. 

220. Whipple, Guy Montrose. Manual of Mental 
and Physical Tests. Warwick and York, Baltimore, 1915, 
2 vols. 



BIBLIOGRAPHY 343 

221. Witmer, Lightner. Children With Mental De- 
fect Distinguished from Mentally Defective Children. The 
Psychol. Clinic, 1913, 7, 175-182. 

222. Woolley, Helen Thompson. A New Scale of 
Mental and Physical Measurements for Adolescents and 
Some of its Uses. J. of Educ. Psychol., 1915, 6, 521-550. 

223. Woolley, Helen Thompson and Fischer, Char- 
lotte R. Mental and Physical Measurements of Working 
Children. Psychol. Monog., 1914, 18, No. 1. 

224. Wyatt, Stanley. The Quantitative Investigation 
of Higher Mental Processes. Brit. J. of Psychol., 1913, 6, 
104-133. 

225. Yerkes, Robert M; Bridges, James W.; and 
Hardwick, Rose S. A Point Scale for Measuring Mental 
Ability. Warwick and York, Baltimore, 1915, pp. viii 
+ 218. 

226. Yerkes, Robert M., and Wood, Louise. Methods 
of Expressing Results of Measurements of Intelligence. 
Coefficient of Intelligence. J. of Educ. Psychol., 1916, 7, 
593-606. 

227. Young, Herman H. The Witmer Formboard. 
Psychol. Clinic, 1916, 10, 93-111. 

228. Yule, J. Udny. An Introduction to the Theory of 
Statistics. Charles Griffen and Co., London, 1911, pp. 
xiii + 376. 



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APPENDICES 349 

APPENDIX II 

TABLE XXII 

Records of the Delinquents at the Glen Lake Farm School of 

Hennepin County, Minn. 

Life- Age Basal School Grade 

No. Yr. Mo. Test- Age Test-Age Sept. 1 of Offense 













Life-Age 




1 


9 


10 


VIII.8 


vmt 


3B 


Truancy 


*2 


16 


7 


XIII 


XIII 


12 A 


Grand larceny 


3 


10 


1 


X.8 


ixt 


3A 


Truancy 


4 


12 


4 


XII 


XII 


4A 


Truancy 


5 


14 


3 


XII.2 


XII 


7A 


Petit larceny 


*6 


14 


8 


XIII 


Xlllf 


9B 


Assault & battery 


7 


16 


3 


XIII 


XIII 


9B 


Check, no funds 


8 


15 


7 


XIII 


XIII 


7A 


Burglary 


*9 


15 





XI.6 


xit 


8B 


Petit larceny 


10 


9 


9 


IX.2 


VIII 


2B 


Truancy 


11 


14 


5 


XII 


XII 


9B 


Petit larceny 


12 


12 


2 


XI.2 


XI 


4A 


Incorrigibility 


13 


16 





XIII 


Xlllf 


8A 


Petit larceny 


14 


13 


8 


IX.6 


vmt 


4B 


Breaking & entering 


15 


15 


10 


X.6plusX 


4A 


Incorrigibility 


16 


15 


9 


X.6 


ixt 


5B 


Breaking & entering 


17 


11 


1 


XI.4 


xit 


5B 


Incorrigibility 


18 


14 


10 


XII.2 


XII 


5A 


Indecent conduct 


19 


15 


11 


XIII 


XIII 


8A 


Truancy 


20 


13 


2 


VIII.4 


VII 


3B 


Grand larceny 


21 


14 


1 


XIII 


XIII 


8B 


Petit larceny 


'22 


13 


9 


XI.6 


xit 


6B 


Petit larceny 


23 


11 





XI.2 


XI 


4B 


Incorrigibility 


24 


16 


11 


XI.6 


XI 


7A 


Petit larceny 


25 


12 


6 


XI.2 


xit 


7B 


Truancy 


'26 


12 


9 


XI.2 


X 


4B 


Incorrigibility 




Life-Age 




Basal 


School 




No. 


Yr. Mo. 


Test-Age Test-Age 


Grade 


Offense 


'27 


11 





X.4 


X 


5A 


Petit larceny 


! 28 


15 


7 


XIII 


XIII 


8A 


Truancy 


29 


14 


9 


XII 


XII 


5A 


Truancy 


'30 


11 


11 


XII 


XII 


6B 


Truancy 



350 DEFICIENCY AND DELINQUENCY 

Life-Age Basal School 

No. Yr. Mo. Test-Age Test- Age Grade Offense 

*31 11 4 IX.8 IXf 4B Truancy 

*32 15 7 XII XII 7 Vagrancy 

*33 13 9 XI.4 Xlf 5 Grand larceny 

*34 13 8 X.8 X 5 A Petit larceny 

35 16 6 XII.2 XII 8 A Burglary 

*36 10 8 IX.8 Vlllf 3B Incorrigibility 

*37 14 10 XI.6 Xlf 7B Grand larceny 

*38 13 8 XIII.O XIII 8B Disorderly conduct 

*39 14 1 X.8 Xf 4B Truancy 

40 15 2 XI.6 XI 7B Petit larceny 

•41 9 9 X.2 X 4B Truancy 

42 11 5 XI.4 XI 5B Incorrigibility 

*43 7 8 VII.6 VII 2B Petit larceny 

*44 13 11 XI.6 XI 8B Grand larceny 

*45 15 1 XI.6 Xlf 9B Burglary 

46 13 10 XII XII 5B Incorrigibility 

*47 10 6 IX.2 IXf 5B Truancy 

48 14 1 X.2 Xf 6B Burglary 

49 14 3 XIII Xlllf 8B Burglary 

50 14 7 XI1.2 Xllf 8B Burglary 

*51 13 2 XII.2 XII 8B Malicious destruction 

of property 

52 13 6 X.2 X 7B Petit larceny 

*53 13 7 XI.6 XI 6 A Burglary 

54 14 3 XI.6 Xlf 5 A Incorrigibility 

55 6 VII.8 Vllf IB Petit larceny 

56 15 XII.2 XII 8B Incorrigibility 
*57 12 XI XI 6 A Petit larceny 
*58 15 XI.4 Xlf 7 A Petit larceny 

59 15 9 X.4 Xf 6B Petit larceny 

60 15 1 XIII XIII 7 A Petit larceny 
*61 11 3 XI.4 XI 4 A Truancy 

62 12 XI X 3 A Truancy 

*63 15 3 XIII XIII 8B Petit larceny 

*64 16 1 VIII.8 VIII 5B Trespass 

65 16 4 XII XII 6B Incorrigibility 

*66 15 XI.4 XI t 6B Trespass 

*67 14 5 IX.9 IXf 3 A Incorrigibility 

68 16 XI.4 XI 9B Disorderly conduct 



APPENDICES 



351 



Life-Age 



Basal School 



No. Yr. Mo. Test- Age Test- Age Grade 



Offense 



*69 16 XIII XIII 

*70 15^ 7 XI.4 Xlf 

71 15 8 XI.6 Xlf 

72 16 7 XIII Xlllf 
*73 15 11 XII.2 XII 
*74 13 1 X.4 Xf 
*75 14 10 XI.6 XI 
*76 11 4 VIII.8 VIII 
*77 10 3 XI XI 
*78 13 4 X.8 Xf 

79 15 5 XII XII 

*80 15 4 XI.4 Xlf 

*81 11 XII XII 

*82 12 5 IX.8 IXf 

*83 11 7 XI.4 XI 

84 13 8 XI Xlf 

85 16 4 XII XII 

86 11 4 XI.4 Xlf 

*87 13 9 XI.4 XI 

*88 14 XI.2 XI 

89 16 5 X X 

90 14 9 XIII XIII 

91 13 10 X.4 X 

*92 15 4 XI.6 Xlf 

93 15 11 XIII XIII 

94 12 10 XII XII 
*95 10 10 IX.2 VHIf 
*96 12 4 XII.2 XII 
*97 15 7 XIII XIII 

98 14 9 XII XII 

*99 11 XI.2 Xlf 

100 13 7 X.2 X 

101 10 9 VIII VII 
*102 15 1 XIII XIII 

103 15 5 XI.6 Xlf 

104 9 7 IX Vlllf 



8 B Grand larceny 

7 B Jumping on train 

6 A Disorderly conduct 

10 Taking auto. 

6 A Truancy 
3 A Truancy 
5 A Truancy 

3 A Incorrigibility 

4 A Petit larceny 

4 A Petit larceny 

7 A Indecent Conduct 

5 A Furnishing Liquor 

5 B Malicious destruction 

of property 

4 B Petit larceny 

4 A Truancy 

6 B Incorrigibility 

11 A Petit Larceny 

5 A Malicious destruction 

of property 

6 B Petit larceny 

8 A Burglary 

5 B Taking auto plug 

6 A Petit larceny 

4 B Carrying dangerous 
weapons 

6 B Truancy 

8 B Truancy 

4 B Incorrigibility 
3 A Petit larceny 

7 B Petit larceny 

9 A Burglary 

8 B Incorrigibility 

5 B Incorrigibility 
5 B Petit larceny 

3 B Breaking & entering 
7 A Truancy 

10 B Incorrigibility 

4 B Incorrigibility 



352 DEFICIENCY AND DELINQUENCY 



No. 


Yr. Mo. 


Test-Ag< 


i Test- Age 


Grade 


Offense 


105 


15 


10 


XI.6 


XI 


7A 


Receiving stolen 
property 


106 


15 


10 


XII.2 


XII 


5B 


Incorrigibility 


107 


12 


2 


XII.2 


XII 


7B 


Vagrancy 


108 


13 


1 


X.8 


X 


5B 


Truancy 


*109 


13 


9 


X.6 


xt 


5B 


Petit larceny 


*110 


15 


10 


XI.4 


XI 


6A 


Malicious destruction 
of property 


mi 


12 


6 


XI.2 


XI 


5B 


Petit larceny 


112 


10 


9 


XII 


XII 


4A 


Sweeping grain car 


113 


15 


2 


XIII 


XIII 


9B 


Trespass 


114 


12 


10 


XII.2 


XII 


5B 


Incorrigibility 


115 


14 


7 


XI.6 


xit 


7B 


Incorrigibility 


*116 


15 


10 


XI.4 


XI 


7A 


Incorrigibility 


*117 


13 


9 


XII 


XII 


4A 


Incorrigibility 


*118 


9 


1 


XI.2 


xit 


5B 


Incorrigibility 


*119 


16 


11 


XI 


xt 


7B 


Disorderly conduct 


*120 


13 


3 


XII.2 


XII 


6B 


Truancy 


*121 


9 


9 


IX.6 


VHIf 


4B 


Sweeping grain car 


*122 


11 


9 


X.8 


X 


3B 


Sweeping grain car 


*123 


10 


3 


X.2 


X 


4A 


Truancy 



*Repeater. 

fPassed all tests at the basal age. The others passed all but one 
test at the basal age. 



INDEX 

Ability of the feeble-minded 74, 92, 197 

Arrest of development, see maturity 

Average curves 280 ff 

Binet Scale 7, 172 

Year units of 260 ff 

Borderline of deficiency 5, 13, 304 ff 

For the mature 82-95, 240, 315 

For the immature 104-110 

Causes of delinquency .203 ff, 210 ff 

Method of studying 218, 224 ff, 231 ff, 244 

City jails 148 

Coefficient of intelligence 305, 313 

Conative cases 15, 18, 24-30, 34-40, 239, 248 

Convicts deficient 142 

Correlation: of degee of deficiency with delinquency 217 

Of deficiency and criminality 220 

Significance of coefficients of 219 

Of deficiency and juvenile delinquency 220 

County institutions 134, 148 

Crimes by the feeble-minded 212, 214 

Criminal diathesis 234 

Death rates 30 

Deficiency, nature of 21, 211 ff, 239 

See feeble-mindedness, frequency, correlation, etc. 

Deficient delinquents .'".... 158, 190, 199, 211 ff, 239, 246 

Delinquency, see frequency of, causes of, correlation, etc. 
Delinquents: first offenders 165, 167 

Repeaters 168 

Delinquents, tested: female 128-141 

Male 141-157 

Development curves 252 ff., 279 ff 

Diagnosis 6, 11, 14, 52, 90, 107, 172-176, 194, 197, 201, 241-244 

Distribution curves 267-275, 317-323 

Doubtful cases 18 

Employment of feeble-minded 74-80 

353 



354 DEFICIENCY AND DELINQUENCY 

Environment 42, 225 ff 

Estimating deficiency by schooling 190, 199 

Expert court advice 243 

Family resemblance versus heredity 231 

Feeble-minded not detected by tests 14, 34-40 

Feeble-mindedness 10, 17, 18, 20, 239 

See deficiency. 
Frequency of deficiency 23, 47 ff., 80, 158 ff 

Effect of local conditions 147, 152, 161, 163 

Frequency of delinquency among deficients 211-218 

General ability 34, 45, 282 ff 

Glen Lake Farm School 122, 177 

Goddard's Scale, borderlines 89, 106, 111, 313 

Goring's study of criminals 218 ff., 231 ff 

Gruhle's method 229 

Heredity 229 ff., 236, 244 

Individual differences : 41, 280 

Inert cases 15 

Instability 15, 23 

Institutional care 242, 246, 248 

Intellectual deficiency 10, 17, 20 

Intelligence quotient 304, 313 

Juvenile delinquency and deficiency 220-223 

Juvenile delinquents 162 

Kuhlmann's Scale, borderlines 87-90, 111, 118 

Legal responsibility 244 

Maturity of mind 83, 282, 290 

Later for deficients 294 ff., 230 

Measurement units 254 ff ., 275 ff ., 317 

Mental deficiency 11, 20 

See feeble-mindedness. 

Mental development 279 ff 

Minneapolis; delinquents tested 125 

School retardation 177-185, 199 

Juvenile deficient delinquents 220-223 

Minneapolis, school group tested 85-91 

Morons: chances of delinquency 217 

Danger to society 237, 246 

Normal distribution 256, 267 

Observation home 242 

Offenses 168 



INDEX 355 

Percentage definition of deficiency, 5, 13, 20, 65, 72, 80, 240 304 ff., 307 

Advantages 311 ff 

Percentage feeble-minded 47 ff 

Percentiles as units 276 

Point Scale, borderlines 114, 313 

Prostitutes 78, 129, 140, 158 

Schooling 186 

Quantitative definitions 21, 304 ff 

Effect of uncertain forms of distribution 317 ff 

Ranks as units 276 

Rates of development 290 ff 

Recidivism 168, 235 

Reformatories 128, 143 

Responsibility of deficients 244 

School test of deficiency 177, 189 ff 

School maladjustment 203-209, 247 

School retardation of delinquents 177-188, 190-194, 199 

Skewed distributions 267, 300 

Social care 47-52, 80, 158 ff., 212-214, 216, 237, 242-251 

Social deficiency 10, 15, 74, 239 

Special ability 34, 45 

Special classes 62 ff., 74-80 

Standard deviation 256, 306, 314 

Standford Scale, borderlines 101, 112, 313 

State prisons 128, 141 

State Training Schools 131, 145 

Sterilization 245 

Test by school retardation 177, 189 

Tested deficiency 13 

Tests, mental 170 ff 

See also Binet, Goddard, Kuhlmann, Point, and Stanford Scales. 

Thorn Hill Detention Home 151 

Training for deficients 205 

Units of measurement 254, 275, 317 

Vagrancy 158 

Variability 41-46, 280 ff 

Year units 260-266 



